2004 Ford F150
4x4
OK, so here is the situation.... The truck stalls at Idle or when low RPMS, it was also choking at high speeds when accelerating at about 1700RPM's, the engine light would flash, a wrench shows up and then gas pedal no longer works, sometimes it Revs at about 2500 RPMS for 15 seconds and then drops. When you restart it, everything works, however once the battery had to be disabled for gas to work again. We had the codes read at the garage by us and it came up with 2 oxygen sensors and mass air flow sensor. We replaced them, it drove perfect for a half hour and it started stalling again. We took it into ford and it read throttle body actuator so we replaced that and the throttle body sensor. We used the throttle body cleaner as well afterwards and It is still stalling, we disconnected the battery to reset codes after but light goes back on after 20 Minutes. Fuel pump was replaced last year and fuel filter was replaced when oxygen sensors were done. It has poor fuel consumption and when it stalls there is a gas fume smell however no black exhaust or excessive exhaust. Hoses were checked but there doesn't appear to be any leaks. Could this be the PCM or something else? Any advice would be greatly appreciated..... Also Engine was replaced with new one 5 years ago, has about 125000kms on it.

 

When we unplug the Mass Air Flow Sensor (MAF), the system will substitute fixed values and the engine should run better if the MAF is defective. You might consider trying that, unplug it with the key off, then try it and see if there is any difference. You will get a check engine light ,expect that. All you need to do when done checking is to remove the battery negative cable from the battery post and hold it on the other,positive cable terminal for a few minutes. After about 10-15 minutes ,reinstall the negative cable back on the negative battery post, start the engine ,don't touch the throttle pedal and let the engine idle for a few minutes for it to relearn. You will need to reset all your radio stations .Let us know how you make out, thanks.

You might want to read up on the Evap system because there could be a problem with either the purge or vent valves..Hope you do not keep filling the tank with gasoline after the pump shuts off because that procedure can cause problems with the Evap system.

 

Is your truck misfiring? if it is it is most likely the VCT solenoid under your valve cover. I have a 04 too and mine had the same symptoms. The solenoid is either worn out or just clogged with dirty oil. Run some kind of motor flush out through your engine (via oil fill) then change the oil. For me it cleaned out my vct solenoid and runs great now. If it doesn't work Id suggest checking the solenoid to see if its worn out. Good luck!

 

I believe Itzwyatt brought up a good point. Were there any codes that might have directed you to the VVT system? Might be a good idea to make sure the engine oil is not overdue for replacing since the VVT system relies on clean engine oil to function properly.

There may be more than one problem, but we take them one at a time. What should be considered would be to have a good scan tool check the fuel trims. If the purge or vent valves are borderline they may not throw a code , but fuel trims will reveal if it is running rich or lean and either one of them can cause some of the symptoms you are getting. If the purge valve doesn't have an electrical problem, but has a mechanical problem like sticking open it will not throw a code unless the system is excessively rich.
The symptom of having the odor of gasoline is not normal and is a clue that fumes are getting out when they should be contained if everything is working correctly.
A thorough visual check of all the hoses under the hood in the engine compartment as part of the Evap system might reveal something. Otherwise, more detailed information obtained with a scan tool may be required.