Bad Gas? or what could it be?

[Bob&Pat]

This is the first mechanical problem I have had with this motorhome.

Ford 2002 F53 V10 motorhome with 44,000 miles,misses when downshifting climbing hill and now on take off from a light at low speeds.

I am thinking it is bad gas??

Thursday 1-13-2011 filled up in Kentucky heading south on I-75. A short while later the engine started missing (kind of chugging) climbing uphill, thought it was going to die out but it did not. Did this for the next 60 or 80 miles and then it was running normal up and down hill for the next 30 or 50 miles. And again it started doing the same thing again. Did this off and on for the next 250 or so miles. In Dalton Georgia added 4 pints
of SeaFoam gas additive. Presented the same symptoms on and off for the next 200 or so miles. Changed the fuel filter in Perry Georgia (this makes the third new fuel filter) and symptoms continued for the next 10 to 15 miles and then it ran perfect for the next 100 or so miles, thought my problem was solved. And then the symptoms presented themselves again on and off for the next 200 miles.

I am still thinking bad Gas. I added 3 more pints of SeaFoam on the next fill-up.

Any ideas?

I checked the transmission fluid and it looks clean and is full.Automatic Transmission Fluid and Filter was changed 10/30/2006 at 29,659 miles

[Don/Lou]

Could be water ingestion if driving in the rain??

[JohnRR]

Bad coil or coils?

[hometool]

you could be correct about it being a fuel problem but i have read about spark coil failures on some ford engines i belive thay had a bulitn about it i gess there is a coil for each cylinder and the ones at the rear of the engine would fail i hope this helps lee

[LVJ58]

I would recommend taking it to a Ford facility and have them run a diagnostic check that will perhaps identify the problem.

Along with other causes suggested, it could be a faulty throttle position sensor, crank sensor, and/or mass air flow sensor.

Best of luck resolving your problem

[Topflite51]

Since you did not say anything about a check engine light, problem most likely not with anything electronic. You are probably looking in the right area concerning fuel. Likely culprit is in the fuel delivery area. Something probably wrong with pressure or volume. Most likely is the fuel pump. Have a shop run fuel pressure/volume tests.

[Bob&Pat]

Thanks everyone for your advise.

David you are correct the Service Engine Soon light did not and has not come on.

[LVJ58]

For whatever it's worth, I checked this site:

Ford OBD-II Trouble Codes

There I found numerous trouble codes relating to the fuel pump. Could it possible one of these problems may exist even though the "SES" light failed to illuminate?

Just wondering

[justimagination]

Bob, I agree with you about the fuel problem, if I understand you about not having this problem until buying fuel in KY. It happens a lot especially this time of year. Water is heavier than gas, which causes it to settle in the bottom of your tank and just about impossible to remove an excessive amount unless there is a drain in the bottom of the tank. I do know that the fuel is pulled through the pickup hose that has a sock type filter on it, but it will NOT stop picking up the water. You have to imagine how much the fuel is slosshing around while driving. I don't think it is a FUEL PUMP problem with the miles on your unit, but contaminated fuel. JMHO. Good luck and let us know how it goes.
David G.

[KC1BUD]

I had an old and old at the time I owned it, Dodge Class C. It did this every time I drove it under heavy load, such as pulling a trailer at freeway speeds. I had fuel Filter, the pump and fuel lines changed to no avail. It turned out that it would vibrate the carburetor so much that it would psychically shake it loose and this caused the vehicle fuel to air mixture to be off and would cause the symptoms you describe.

But with modern computer controlled engines, I don't know if this is even possible. Unless it gets in after the mass airflow sensor.

[Shadowcatche]

Check the OBDII codes, folks can speculate forever but that is what they are there for to give you some idea (not fool proof).

[Dirtbuster]

Ford engines are notorious for coil pack problems in high moisture area's. They will usually start acting up between 45 -50 in high gear. It almost feels like a transmission problem, when the engine starts bucking. It is hard to identify the problem, until the check engine light comes on. If you remove the coil pack,spray it with contact cleaner. This will remove any moisture from the coil pack. Then apply die-electric grease to the inside of the boot before re-installation. Also apply some of the grease to the top of the boot, where it sits on the top of the intake.

Hope this might help!

[Topflite51]

The OP'er has stated his Sevice Engine Soon light has NOT come on. A low fuel pressure/volume will not normally turn on the light. Water in the fuel will generally cause an engine misfire and turn on the light, if this happens code error can and does vary. Just my experience.

[Bob&Pat]

The local Ford dealer about 10 miles from our RV park here in Florida called to a follow-up the email I sent him with the same information I posted above. He mentioned the coils and plugs but would have to check it out.

A Truck Service Garage within walking distance from our park suggested I bring it in Thursday 8 am and he would check it with his computer and switch around Coil over plugs to verify if that proves to be the problem. He also said he would test the fuel pressure. I will post the results. Thanks again to everyone for the suggestions.

I am thinking the Truck Service may be less expensive. Plus the Truck Service will allow us in and out of the Motorhome while they are working as long as it is not on a hoist or jacked up.