2004 Ford Ranger fuel issues

2004 FORD RANGER
50,000 MILES • 6 CYL • 4WD • AUTOMATIC
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JMICHAELS
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sometime in the fall I began noticing a major drop off in mileage. Currently I can confidently say I am getting only 10 mpg. I had been getting more like 16 in the city and 20+highway. I have had no problems with this truck or previous Ranger ever. I talked to my dealer who suggested it was a clogged injector so I tried a couple of gas treatments to no avail. Then they thought maybe it was a brake issue--had them inspected and they said everything checked out. I parked it for several days and looked for obvious leaks and found one small gasket leak around RF axle so I had that taken care of but it has still not solved my underlying issue. It seems that even just turning the engine over causes the gas needle to drop. Where is all the fuel going?? I drove six miles round trip to my wifes work and it was like someone was siphoning my tank! I have no obvious leaks like around the gas tank or anything like that either which makes this all the more puzzling. Oil and air filters have been changed recently and are done on a regular basis. OBD did not help since I have no check engine light.
Is this a fuel pump issue? spark plugs? timing? My dealer does not seem to have any ideas and I am increasingly frustrated.
Jan 15, 2010 at 8:16 PM
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MERLIN2021
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Can be anything from a bad MAF sensor, bad thermostat, bad alt/regulator(low VPWR). I sent a PDF for you to look over, you need a scantool to look at Long term fuel trims, and check the chart for the right test.
Jan 16, 2010 at 10:00 AM
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JMICHAELS
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I read about the MAF sensor somewhere else and I did clean it which didn't help but it could be defective also. could you explain how the thermostat or alternator could affect mileage? What is VPWR and "longg term fuel trims"? Sorry I am not up on the lingo.
Jan 16, 2010 at 6:03 PM
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MERLIN2021
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If the motor never warms to correct operating temp, it will stay in open loop and run extremely rich as it does in open loop, in closed loop the 02 sensors are added and so is EGR, 02 sensors are probably along with the MAF the most important fuel control sensors on the car. Low voltage does not allow the PCM to operate correctly! It is unusual for any of these sensors to be bad at 50,000 but not impossible. A thermostat or the ECT(engine coolant temp) sensor may be the place to start here. Does upper radiator hose get VERY hot? It should be cold until the tstat opens, then get hot. This should take 5-10 minutes. Testing a thermostat requires either a infrared thermometer aimed at the thermostat housing, or removal and suspend it in boiling water and a thermometer to see what temp it opens at. Did the dealer test the fuel pressure and fuel pressure regulator? I also need the engine size in liters, 3.0 or 4.0?


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Jan 17, 2010 at 7:20 AM
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JMICHAELS
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it is 4.0 L. It seems the thermostat would make the most sense since it seems to use a lot of fuel at start up and with my local commute since the engine may not warm up or fast enough.
Jan 17, 2010 at 7:31 PM
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MERLIN2021
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Let me know if you need any more help with this, I would like to know how it resolves!
Jan 19, 2010 at 5:11 PM
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JMICHAELS
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I am waiting to get an appointment to get those things checked out. I was also wondering about my serpentine belt. Visually it doesn't appear to have any cracks but in the largest span (maybe 6 in.) I have a half inch of play (between main drive and a/c comp.). Does this sound about right or not?
Jan 23, 2010 at 4:23 PM
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MERLIN2021
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Shouldnt be a problem, no chirping or squealing?
Jan 24, 2010 at 5:48 PM
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SCHUMACHERT
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I'm experiencing the same problem with my 02 Ranger, extended cab, 4x4, 4.0 V-6, automatic, 59000 miles. Did you find a solution to the fuel consumption problem?
Feb 6, 2010 at 9:24 AM
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MERLIN2021
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Usually if I dont hear back from the questioner, it's been solved, did you test as I described?
Feb 7, 2010 at 10:58 AM
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SCHUMACHERT
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I bought a thermostat and will be making an appointment to have my cooling system flushed this week. After the fllush I'll install the thermostat and watch it for another tank full. I just filled my tank with gas, documented 11.8 mpg and added a fuel system cleaner/additive. I have also located the MAF on the truck and was given some advice on how to clean it using carb cleaner or ether although I don't want to do too much at once or I won't know what the fix was. I must be honest and add that I also realized I only had 15 psi in my front tires so now all the tires are at the mfg recommended pressure. I'll be watching it over the next 45-60 days as I dig deeper.
Feb 9, 2010 at 11:56 AM
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JMICHAELS
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I am having it tested on friday the 12th. I had planned to do it sooner but the two blizzards set that back. I will let you know the results.
Feb 11, 2010 at 6:52 AM
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MERLIN2021
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Dont use either one to clean the MAF, MAF spray cleaner is now sold...cleaning usually does not work.
Feb 12, 2010 at 3:06 PM
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JMICHAELS
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Dealership ran dignostics and said they found no error codes. I asked them about the thermostat, MAF, PCV etc and all they told me was that nothing came up as errors. What that tells me is that rely too much on the computer to tell them what is working instead of checking each component. They did do a fuel trim ck and said that I was getting 18-19 mpg highway but that they can't figure it for more local driving. So as of now I have had no resolution to this issue. If the dealership where I bought it doesn't seem to want to dig in and investigate it more I guess I am stuck for now.

The last couple of mornings I have gotten a wiff (inside cab) of gas upon start up. Don't know what that might mean. I think my next move is to replace fuel filter and plugs and see where that gets me.
Feb 17, 2010 at 7:05 AM
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MERLIN2021
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No codes will show up if the system runs normally! If it stays in the wrong mode, as in warm up, it will run rich, beacuse it's designed to! You need to test the ECT and thermostat as I posted. OBD II scanner is only as good as the problem, if the PCM sees no porblem, it wont set a code.
Feb 17, 2010 at 1:41 PM
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JMICHAELS
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I asked them to do that and I guess they are just stonewalling me. I need to find someone in my area that is willing to do some homework. I will keep after it.
Feb 17, 2010 at 3:51 PM
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MERLIN2021
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Have you done anything with the ECT or thermostat yet?
Feb 17, 2010 at 4:46 PM
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SCHUMACHERT
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I aired up my tires to the recommended psi. I've replaced my thermostat after having the cooling system flushed. Since doing that I got 10.8 mpg and 11.8 mpg on the next 2 tanks of gas.

I'm not getting any faults either so there is no sense going to the garage. I also believe they rely on the computer too much.

I will look into MAF cleaner.

What is the ECT?
Mar 15, 2010 at 7:17 AM
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MERLIN2021
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ECT= Engine coolant temperature sensor. It acts like a choke for EFI engines. If it tells the PCM that the engine is cold, it will supply more fuel...Clean the throttlbody with the engine off. Use a rag and spray throttlebody cleaner into the rag. Pressure test the fuel system, yours has a Mechanical returnless system, if the pressure regulator isnt working right, too much fuel could be sent to the injectors. Pressure should by 30-65 psi.
Mar 15, 2010 at 2:26 PM
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JMICHAELS
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I had some surgery done and have not been able to visit this problem for a while.

I flushed and filled coolant and replaced thermostat along with fuel filter. After I track mileage for a couple of tanks I will get back to you with results.
Apr 3, 2010 at 4:21 AM
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MERLIN2021
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OK I'll check in again, Good luck with the recovery!
Apr 3, 2010 at 8:47 AM
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JMICHAELS
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Because I have had surgery I had a local independent shop do the work. I had found a good website detailing the removal of the thermostat and I was surprised that the shop charged me for an intake manifold gasket as well as a EGR valve gasket. Neither of these appeared in the help I found on line. What do you think of this? Are they just ripping me off?
Apr 3, 2010 at 11:37 AM
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MERLIN2021
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Did they say if they found a vacuum or coolant leak? These dont need to be done if you only needed a Tstat...
Apr 3, 2010 at 10:37 PM