Runs rough

No compression will definitely cause misfires. I would start with a cooling system pressure test to see if the head gasket failed. Then probably just pull the head and see what is going on for sure. For it to lose compression on the entire bank suggests a major failure. Please check out this guide it should help

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please run down this guide and report back.

Pressure test held fine at 15 lbs. No leaks and no coolant in oil or vise versa.

Hmm, run a leak down test and see if you are losing compression across the cylinders. Could be the gasket let go right between the cylinders. Just not that many places for compression pressure to go. Valves, rings, gaskets or cracks.

Well I started tearing it down and got to the upper intake manifold and stopped. I found that 2 of the injectors were melted no oring or plastic tip left plus I was leaking fuel. What could cause this and should I go further. Any other possible damage?

This can cause the damage but replacing the injectors will not help the compression come back. There must be some kind of damage internally like a leaking valve or piston ring issue.

Keep tearing it down.

Let us know what happens and please upload pictures or videos of the problem.

Cheers, Ken

With that description I'm going to say you have burnt intake valves. That would let the flame travel back into the intake and melt things.
You will need to pull the heads to check on that.

I have a '97 F150 with 4.6 V8, automatic transmission, 4x4. The truck was not used for approximately 1 year prior to me purchasing it. When I first purchased the truck it had a slight spark knock during acceleration, slight miss that seamed to clear up and would die when you came to a stop after driving when it was at operating temperature, unless the AC was on. But it was drivable.

Then it would sometimes exhibit a no start condition until it was cranked for several minutes. When it did start it would run really rough,like it had a miss fire or vacuum leak, but would clear up and run okay.

Now it runs rough anytime you start it up, seams like a bad misfire. It can be driven, however you can not accelerate fast or it sounds like it has major spark knock. I have replaced the sparkplugs with autolite platinums, new plug wires, removed the throttle body and spacer and cleaned the carbon deposits from them. Also cleaned the IAC. Also during the whole ordeal there has been no check engine light.

I have read many threads that point at a large range of possibilities but all of the threads have noted a CEL was on. As I have pointed out, I have no CEL on. This could be due to the truck not being driven for very many miles. Trying to avoid the high cost of taking to the dealer, but I am at my wits end for what the cause could be. Any help would be greatly appreciated.

try taking the vehicle to a good autoparts store (autozone etc.) have them check for codes .. most do this for free .. with the faults you are describing codes should be showing ..let me know !

Thanks. I will take it and see if there are any codes.

I am having he exact same problem as you are however mine started happening after I got a batch of stale fuel the other day. Starts pinging when under load however when i rev the engine in park there is no ping. Could you Let me know what you found out?

MIGHT WANNA GET THOSE CODES CHECKED.....YOURS MAY BE DIFFERENT THAN HIS, HE DID NOT POST HIS.........

ARE YOU "ALL CAUGHT UP ON" SCHEDULED MAINTENANCE?

DID YOU RUN A FUEL SYSTEM CLEANER THRU, SUCH AS SEAFOAM?

GET THE EXACT CODE NUMBERS......YOU CAN LISTEN TO THE FELLER CHECKING YOURS.......THEY CAN BE INTERPRETED IN DIFFERENT WAYS

IT'S SORT HARD TO "OBJECTIVELY INTERPRET": "THE MAN SAYS IT'S THE EGR"....WHEN THE MACHINE (SCANNER) ACTUALLY SAID (EXAMPLE) "P0442"

RETURN WITH YOUR INFO, SOMEONE HERE SURLY WILL ASSIST YOU!

THE MEDIC

my truck sometimes runs rough but you can stay on the gas and it will clear out. i have changed the fuel filter,any suggestions?

try cleaning maf sensor and running some ford fuel injector cleaner. check plugs, air filter, check vacume lines for leaks. spray some carb cleaner while running around vacume lines and plentum /intake manifold gaskets for small leaks. if it picks up when u spray then thats your problem.

My f150 runs rough and sometimes backfires at the engine when slightly accelerating around 40 t0 60 mph. runs fine with hard acceleration. it was only doing it once in a while, but now its allmost all the time. I changed the tps and there was no change. also there are no trouble codes. plug wires and new plugs are on the list for tomorrow. I am thinking maybe slop in the timeing chain?

Hi:
I would start with a comprssion test. You may have low compression which can cause the problem you described. If you need directions, go to:

https://www.2carpros.com/dia/how_to_check_compression.htm


Let me know what you find.

Joe

My truck killed at a stop sign It would restart but only kill at the next stop. Eventually it would not run 1 block. With my foot on the brake it would idle rough and sometimes lurch forward.
I towed it home and changed the fuel filter but it still kills after 1 minute.

Has the check engine light come on? Have you checked for vacuum leaks?

Let me know.
Joe

The engine light is on. The parts store analyzer code was for a random miss and the O2 sensors. I havent done any further work on it.

When were the plugs replaced last? Also, do you have the coil over each plug on your truck?

The plugs were changed about 5 years ago; There isnt a coil for each wire.

If the plugs haven't been replaced for 5 years, I would start with a new set of plugs, wires, distributor cap, and rotor. Chances are you put a good many miles on it over 5 years and need replaced. I would try that and see if it makes a difference.

After the engine warms to operating temperature and I shut it off, if I come back after about 30 to 45 minutes it starts but idles really rough until I put it in gear and pull off. What's going on?:

I would inspect really closely for vacuum leaks and split vacuum lines, also what condition is the ignition system, spark plugs and plug wires? spray the spark plug wires when it's dark out and check for spark escaping the wires. Let us know what you find.

Engine Performance problem
1996 Ford F150 6 cyl Two Wheel Drive 180 miles

my truck wants it runs for about 15 min will just running bad and you can start smelling gas

Have you checked fuel pump pressure? You may have a bad regulator. Also, has the check engine light come on?

Let me know.

Joe

Have you checked the regulator? Also, let me know if the check engine light came on.

Joe

no i sure havent noticed a check engine light

You need to check the fuel pump pressure and the regulator. If you need directions, let me know. Also, let me know what you find.

Joe

Around town it's fin e but sporadically struggles, then surges @ higher speedson the highway about 15 minutes in, acceleration stuggles then takes off, then check engine light comes on and its fine for a 5 minutes, then does same pattern again

get the code number for us to further help you. it could be a fuel delivery issue, cat converter or mass air flow.

have you changed the plugs and coils lately??

Roy

truck has a I-6 engine, automatic, fuel injection, 1995 f-150 filled with gas drove 200 miles towards home. truck progressively ran worse. upon arrival home parked and truck will not start back truck was running great prior to this trip.

Not very descriptive but from what I can tell, the only thing that changed was the gas. If you filled from a tank that was recently filled from a truck, debris would have been stirred up that could have gotten through their filters and into your tank. There could be water in that gas too that had been settled on the bottom of their tank. That would clear up after you refill again. There is also a screen in the pickup assembly in the tank that can get plugged. That is more likely to be related to the 200 miles vs. the gas. A plugged screen will not clear up after you refill the tank.

1995 Ford F-150 4X4 mileage: 71,250. My truck starts hard when cold (six to eight turns). Once started, it runs well for about two to three miles until the EGR valve kicks in. Then the engine stumbles/skips for about two miles. However, when the engine does warm up and the temperature gauge is in the normal position, everything is fine. I have replaced the EGR valve, but it has not improved the situation. I have talked to several mechanics that have said that it is engine design flaw concerning the fuel distribution to the fuel injectors. The fuel doesn't get to all cylinders in time when the engine is cold. Have you heard about this? Do you have any suggestions or do you know of any aftermarket fuel system changes that you could recommend to avoid this problem. I am running out of ideas and Ford doesn't seem to have answer to fix the situation. Thanks for your time and help.

We do not think the EGR valve is causing your problem. Replace the temperature sensor as it may be giving false readings to the ECM. Then, scan the ECM for stored fault codes.

I am having a problem with my 95 F150, 4x4, manual tranny, straight 6 pickup. It is having a problem where it lightly "bucks" when driving at a steady speed. When idling or accellerating everything seems fine and runs smooth, but has the rough type of cutting out while at a steady speed and load (40 - 45 in 4th, but also in other gears too).

I changed the fuel filter, performed tune up (plugs, wires, rotor, and cap, air filter) with OEM parts. Thought maybe fuel pump, but it occurs regardless of which tank I use. The thorttle body was also cleaned and I have used injector cleaner in my engine a couple of times. A friend took a ride with me and said he didn't think it was fuel. Could it be something with the tranny? computer? Could this be tied to the EGR?

Any assistance would be appreciated.

If the RPM's are around 1500 to 1800 it is the fuel pump. I have a 91 and it does the same thing. My front tank pump finally died so right now I am running on the rear only.

I was originally thinking it might be that, but it happens the same using either tank and istn't the fule pump in the gas tank? If so, it would be too odd that both go out at the same time, isn't it?

A modification to my original post...

I notice that it doesn't happen when it is cold, but when my temperature gauge gets to the line at the bottom of the "normal" range is when it begins.

I wish I had a tach so I could nail it down to certain RPM's, which would be helpful.

Ford had a recall about the fuel pumps and the transfer switch. Here is one of the many links about the fuel switch. They used a similar system until about 2000 so it should pertain to your truck also.