Fuel Economy

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If that doesn't cut it, you might switch over to an early model Dodge Ram, This would probably handle the mild S.C roads really well in your region.
It may lack power over in my neck of the woods.

------The Medic

fuellmileage is up to the driver on how hard hepresses the gas pedal.keep air and fuel filters clean make sure your injection is working good as alot of those broke the spider and would leak fuel. keep in 2wd as much as possible lastly you could change gear ratio would make it slower but you would also have to do both axles so expensive.

Guys I'm basically looking for places I can cut some weight to help out. I'm stopping and going 600 times in a day. My lead foot isn't making much difference there. I can granny drive it and not do much better. I've tried.

In the past I'd removed the back seats to create more storage space. While storage space isn't an issue anymore, it might help to drop that 100 or so pounds of weight. Maybe gutting the door panels?
100 I wasn't addicted to AC I'd drop that whole system. What if I put a higher temp thermostat? Like a 210? Would that help much? But then I'd be increasing pressure on older parts so maybe that's a no go.

I can gut the cat and put a non fouler on the downstream O2 sensor to keep the light off. I know that'll give me a little boost.

Where else can I cut some weight?

Hmac, I know those things are generally true, but when you're driving 75 feet at a time, granny driving vs lead foot doesn't make a whole lot of difference. I promise. I've tested it. Maybe 1/2 gallon on the day but it cost me 1/2 hour extra of my life that I was not paid any extra for. So the cost: benefit ratio just isn't there. What I need to do is cut weight and get it where it burns less fuel at idle, because most of the day it's idling.

Gutting the cat isn't going to do anything to help the mileage, they are very free flowing on them and if it's working it isn't changing the fuel mix. Higher temp won't help either as it's not designed to use the higher temps and will just stress the system more. My 02 averaged about 18 mpg normally, that's because the 4.3 was built from the 350, it's a reliable engine but wasn't built for economy. Plus you are driving about the worst possible way for economy short stops, on and off the gas. Takes a serious weight reduction to make any difference in those conditions. Not really much to remove that will help with that.

I have seen a minor increase (maybe 1 mpg) when switching to the newer individual injectors from the old spider units. Beyond that they just were not built for mileage.

Up here the current mail dude has two vehicles, one a 4X4 Nissan and the other is a Kia Soul The Soul stays parked at the PO and he drives the one needed for the conditions and amount of mail, like he was telling me, 80% of the time it's a few parcels and lot's of junk mail and such. The Soul is a LOT better on gas but isn't real good in heavy snow. So in the winter it gets parked in his garage and he runs the Nissan full time.

Ok. How much dead weight do you think I could stand to lose? I dropped about 100 pounds of extra unused crap out of the trunk the other day. I'm going to remove the back seats soon. I was also thinking about dropping the hitch but I really do like having it there. It's nice to know I can randomly tow shit. Where else can I shave some dead weight?

If I were able to get my hands on a tuner for it and maybe drop the idle by 50 RPMs might that make a difference in the aggregate?

Basically guys, I know I need to buy something smaller. But that's not in the budget. Free/cheap improvements, however, are.

Rule of thumb is 10% weight reduction gives you 1% mpg gain, but that is over a longer test run, stop and go isn't likely to yield that. Lower idle won't help much as you then need to apply more pedal to get moving plus most tuners don't allow idle speed changes due to that requiring a remap. Low resistance tires made for mileage might help but they are also going to be stiff and slick compared to an all season. Sorry it's not more helpful but they were just not made for mileage.

to bad you can't get a hybrid as they only run on electric to about 6 miles an hour

Youre kind of in a pickle but for your cost vs options I would say for the money and work your biggest improvements are, switch to full synthetic oil. That will give you a little and the biggest bang for your buck as odd as it may seem would be to switch to load range E tires and run 80 psi in them. Those 2 things will reduce a ton of load and drag. You would be shocked at the difference just the tires make. 32 psi in tires puts a heavy load on a motor. If you dont believe it just try pushing a car with 32 psi and then push one with 80. Massive difference. I switched my truck to load range E with 80 PSI and went from 15 to 19 MPG. It is alot rougher ride though. You can switch to syn in the diffs too. Frictional HP costs alot of gas.

I've run the numbers guys. On a 55 miles route, I'm getting 8.2 mpg. If I can get that 10 mpg somehow, it'll save me $72/month. I'm not looking for much, just a little bit. So the back seats are coming out. Going to pop in a new fuel filter (I've put 35k on since I got it and haven't changed it yet so it's probably due). Make sure the gas cap is good. With 180k on it, gutting the cat might be in order. I've got a buddy with a welder that owes me a favor and I've got an O2 sensor non fouler to fool to CEL.

Can you think of any other spots I can drop weight? This isn't a family car, it's a workhorse, so I'm not real worried about interior cosmetics.

Today I ran a route that's a bit longer (63 miles) with fewer stops. I also unplugged the AC compressor clutch because, whipped I don't run the AC while working, it does constantly cycle the system even with it off. I managed a whopping 9.2 mpg today. Maybe it was the reduction in stops, maybe it was the disconnecting the compressor clutch. I'm running the same route tomorrow and will leave the compressor clutch hooked up and see what it does. Should be interesting. Also, I took a dash cam video in case anyone was interested in seeing what I do from my perspective.

The AC in that shouldn't cycle on unless the AC is in use or the defroster is on, if it is you have a controller issue.

I've switched the controller out for a different issue but it still does that. My 2002 did it, as did my last 2000. I was pretty sure it was normal. I thought it was part of some moisture control junk they were doing. If memory serves they've done it on many models. Maybe I'm wrong though

None of mine worked that way the 97, 01 and 02 only cycled if you are in defrost or AC or if you are running any part of that, the idea is that it runs the air through the AC system to dry it if you are running defrost so you don't fog or ice the windshield. The 85 and 92 I had didn't work that way though, those didn't use AC unless it was on. Understandable though as the 2.8 was anemic enough without the extra load and the 4.3 was better but didn't have that system. I had one with a 2.2 in it for about a week, that thing could barely get away from a stop sign. If you've ever driven one of the LLV mail trucks, they were better than the Blazer !

Indeed I've driven both the 2.2L Blazer and the LLV. I use a LLV every other week on Sundays. I one managed to clock 0-60 (GPS verified) in under 17 seconds by working the shifter like an old 3 on the tree while literally standing on the gas. Honestly, the LLV is darn near perfect for what it does and I doubt they'll top it with the next truck. The new one may be nicer, but I see it being problematic and our "less-than-stellar" won't be able to handle it. I've literally diagnosed the LLV problems for them only to find the truck with the exact same problem the day after they had it in the shop for a week. And it would be as simple as a stuck thermostat. I can't wait to see what they can do with post 1980s tech and AC

Speaking of LLVs, here's what's happened the last time I drove one. If I had to guess I'd say a mechanic didn't tighten the pulley bolts. Happened as I was merging onto I-40 (following GPS against my better judgment)

Getting back on track here, if cutting 10% weight generally results in a 1% fuel economy bump, I would think that my type of driving would be doubly or triply helped, seeing as it's mainly going to go towards acceleration, which is all I do, allowing me to take my for if the pedal earlier. Also, a nice little side effect is maybe my brakes will last a little longer. No matter what I use, I don't get more than 3-4 months out of a set of front pads.

I second the 80 PSI in the tires. Without switching the tires, run the PSI as high as you feel comfortable with. Also remove any roof racks or other things in the air stream, and strip all the weight out.
Dump the mechanical fan for an electric model.

I've thought about switching to an E-fan before but right now I'm just trying to go for free or dirt cheap mods I can do while saving cash to buy something else to use on a daily basis. Thinking I can get a little 4 cylinder beater car that runs good to use most of the year and just use the Blazer as a daily driver and run it only as needed on the route.

As for the tires, they're brand new and under warranty so I'm not into doing anything to them until I have to right now.

I filled the tank the other day. Ran a route 2 days straight. Filled it up on the way back to the office at the end of the second day. 126 miles driven on the trip meter, 16 gallons of gas to refill. I swear it used to do better than that. I didn't always track it, but I used to be able to go through 2 days and not be sweating it with the gas light on at the end of the second day. Sometimes I could push halfway through a third day before the light came on.

I've got no engine light on, no codes, the air filter is clean.

I've got the day off Monday. Maybe I'll dig in under the hood and start a general tune up.

What gas are you running? Ethanol added crap will give you less mileage than pure gas. The problem is that most of the ethanol free stuff is also high octane and expensive compared to the booze fuel.

Shell 87. Same crap I've been running from the same station for the last 8 postal years. It's the only branded gas station in town. Only time I run stuff from the other places is when there's an oil shortage and I have to buy whatever I can find. I wouldn't mind running ethanol free, but the only place I can get that is well out of the way and is about 60 cents/gallon more so any gain is offset by the price difference anyway.

I've got a game plan for tomorrow. I've got 4 new ACDelco plugs in my tool box plus another box coming tomorrow. So I'll drop those 4 in the back 4 cylinders and inspect my wires while I'm at it. Beat the dust out of my air filter again, maybe even change it. Work on cutting weight. Who knows? Maybe I'll get an extra MPG or 2 out of the deal. At this point I'm just trying to save up to buy a cheap 4 banger out of someone's yard and get it going. I've got my eye on a cavalier that's sitting at a mechanics shop. I know the old lady who used to own it so maybe that's an avenue for me.

Speaking of air filters, does anyone here think I might notice a real gain with my type of driving if I switch to a high flow filter instead of just the regular $10 ones?

After 3 years of owning this truck, and believing that it has been very well maintained by the original and only other owner because everything under the hood is dated with a mechanics marker (including the distributor), through closer inspection, I've come to realize that it still has the original plugs and wires in it. Yes, after market distributor, but original plugs and wires. I pulled the wires of of cylinders 1 and 5 (easiest to inspect when also rotating tires and checking brake pads) and the wires disintegrated. When I took the plugs out, I saw they were the original ACDelco 41-993s that come with this truck. The same ones that I'm replacing them with.

Since I don't have a set of wires handy, I borrowed a pair of wires off of another non-running vortec my dad has sitting at a mechanics shop and popped them in with 2 new plugs. I ordered a set of 10mm wires that'll arrive tomorrow. Once they come I can finish that up and remeasure my mileage. Hopefully I'll get a nice gain out of that.

Funny thing is even with the old plugs and wires in it, it still fires right up and purrs perfectly. Smooth idle, no misses, no backfiring, no hesitation. But with 180k on it, and 21 years, and a gazillion hours, that's got to be a part of the problem. I shoulda known...

Haven't had the time to tinker with it in the last few days but I did get my new plug wires in the mail. Just a suggestion, if it comes up in the future, you might suggest to customers to do something similar to what I'm doing here. Instead of just buying a set of wires purpose made for the 4.3L, I bought a set of performance wires for a small block or big block Chevy, which had the same ends on the wires, just a couple of extra wires, and they're a bit longer and 10mm instead of the regular 7 or 8mm. I don't know those wires will give much boost, but I'll have 2 spares in the toolbox and they won't perform any worse than the OE ones. Plus they were only $31. Paired with brand new ACDelco 41-993 plugs, maybe I'll save a quart/day, which will add up quick.

Here's a link to the wires I bought in case anyone is interested:

https://www.amazon.com/dp/B07LF95HLR/ref=cm_sw_r_cp_apa_glt_fabc_02JTVVC53HWXEZGP6SS2?_encoding=UTF8&psc=1

Well I finished up the plugs and wires. With the new ACDelco plugs and 10mm wires I did get a good carbon burning smell when I first started it and let it idle for a bit. I revved it a few times and it did ok but stumbled a bit in the 2-3k range. So I took it for a drive. First off I'll say I "think" I've got a better throttle response now. I drive it kinda hard. And it performed well. Hit it's gears fine. 0-80 was smooth. So the power is there. But at 1/4 throttle, there is a stumble on the 2-3k range still. It got better as I drove the truck, so maybe it'll work itself out. Or maybe it's time for some seafoam down the intake...

Any other ideas?

No lights. No codes, of course.

The image below is the from infamous cylinder #3 that many people hate fighting with (takes about 10 minutes if you know what you're doing). It definitely has some age on it. And it matches the other 5.

Look at those OSHA safety shoes LOL.... That plug is easy if you know the trick, or bought the specific swivel socket for it...

regarding your air filter it should be changed once a year along with fuel filter if dusty gravel road conditions more often on air filter. the other type you mentioned are good for filtering rocks out. or racing not much else. you can't put in (air) more than the system was designed for.

No such thing as OSHA in my own garage. But are these better? They're my postal approved shoes.

HMAC that's what I was thinking but I just didn't know if it might make enough difference in the throttle response to actually help with my type of driving

it effects fuel mileage not throttle reponse as well as dirt through the engine

Those are a bit better... Air filter wise, unless you are replacing one that is full of dirt I've never seen any real increases, unless you are running a vehicle that really needs a lot of air like a blower or large turbo otherwise they pass a LOT of dirt and crud, plus the oil tends to mess with the MAF. Speaking of oils, you might try putting synthetics in all the boxes, might give a bit more.

On a hunch, I pulled a wire off of the distributor and compared the contact to one from an old wire. It's considerably more recessed into the boot. Probably by an inch. That would explain why I was thinking I heard arcing going on back there but I couldn't place the sound for sure due to my poor hearing. I'm thinking the random miss (I did finally get a P0300 code yesterday) code is due to a lack of contact between the distributor cap and the wires. So I'm going to shave 1/4 inch off of the boots and see how it goes. I'll shave another 1/4 inch off if needed.

What do you guys think?

Well I cut that 1/4 inch off of the boots. And then a little more off of the ones on the odd side of the engine because they still snugged all the way up to the cap. Now there's only an occasional miss. Much better. So I'll tinker a little more when the engine cools again. I also ran done seafoam through the brake booster line. That ought to get rid of any remaining carbon. I know it's a backyard mechanic trick, but it does work. Sky's the limits here. Maybe 10 mpg before long. And I still haven't got to the weight cutting.

Found you the solution to the problem, Right hand drive, enclosed van, 4X4, diesel available.
Not real cheap but a good solution rarely is... https://www.vanlifenorthwest.com/forsale

I was just there today, these four got to the yard within the last year (since the last time I went)

Revert back to the "Proven" / "Accepted"/ "Reliable" mail method. Inexpensive parts.....computerless.....permanent Code "PO (post office)EZ FIXIN'"

With the money you're spending, one of these could be back up and running with proven MPG modifications!

I feel like one of them will make it back to my house, hopefully a deal (as he's given me in the past) He and my brother and law are best buddies!

They might stop calling you the "mail blazer"/ "mail van" and you earn the "Mail Man" designation as did all of the previous Postal "JEEP" drivers were called!

The Medic

This is a costly idea, but would save you gas in the long run. They have software for remapping the fuel strategy. I watched a video on a shop that does it to hondas alot. it was pretty amazing, the software they were using had pre-sets for more power, better fuel economy, and settings in the middle. Obviously it changes the injector pulse with and shift timing etc. But theres some really cool stuff out there. Id do that instead of throwing a different motor in it. You'd have to buy the software and special scantool the plugs into the obd2 port. Google remapping fuel strategies. See what you can find. Atleast with a remap you wont be losing any power really. It will be running at a different air/fuel ratio, leaning it out but also compensating for it. Just a wild thought.

Just don't get caught remapping and vehicles in the US. The EPA is just waiting to go after folks...

Eh, it's 21 years old. I don't think the EPA would be watching me too closely. Besides, I get stopped at license check points and they never bother actually checking. They just assume it's valid because I'm a mailman. That fuel remaining sounds nice but pricey. But I'll definitely look into it. I know a lot of people around here, maybe someone has the right scan tool for the job.

For right now, I'm looking deeper into cutting weight if I can get some time and maybe gutting the cat.

I will say that with the plugs and wires done the beast is running better than ever. I even did a mean rain assisted burnout the other day

So, my brake booster died the other morning. I haven't had time to put another one in yet (can't get any time off, busy busy at home, you get it). Been riding routes slowly and carefully. To a point where it's taking me an extra hour and a half to run. But, it seems my fuel economy is up. Now I know some will say that's due to granny driving. And maybe a little is. But it needs the question, since I disconnected the brake booster with the massive vacuum leak, could that be giving me any serious bump in mileage? Is there a way to really see? Because I don't plan on driving like my normal self until it's fixed (maybe tonight).

If it is causing that much extra fuel use, is there ab affordable and safe way to convert it from a power brake system to non power brakes?

I know it sounds crazy. Just a thought.

I believe every thing that is vacuum is supposed to be a closed system.

Basically hydraulics, except in "Air" form----No air gets lost or gets added---just on or off actuation

The exception being the PCV, it's sorta like a vacuum cleaner, the air that passes thru it is replenished thru the other end(s) of the valve cover, usually via an air cleaner or a filter.

The "Extra air" the PCV draws in constantly is calculated into the needs of the carburetor (stupid #s example---92% or combustion air goes into the carb's throat----8% comes thru the PCV) ===The 100% used to mix with the fuel to get the mix as perfect as possible.

Stoich or 14 air to 1 fuel ratio

Cutting off (plugging PCV) or adding additional air (a vacuum leak--like the Booster) will mess up the correct burn-----MPGs will suffer in either scenario. Too much or too little air.
-----The Medic