'04 F150 5.4L Running bad with no codes - Ford Forums

GS123 · 03-07-2009, 16:04

Have a '04 F-150 (non Heritage) with the 5.4L. The truck has started to die at idle at times, sometimes taking three attempts to restart. Hesitate during acceleration at times. Hesitate at freeway speeds, feels like the ignition was turned off, but then kicks back in. During one of these freeway hesitations I punched the gas and the rpm suddenly kicked up with no increase in speed like the truck was in neutral. Once the rpm came back down, the transmission engaged again. The truck is not coding, the check engine light does not come on and without the codes, the dealer says he can't fix it, $100 please. I am thinking the PCM is bad, but if anyone has any other ideas, I would appreciate knowing about them.

Thanks in advance!

**360ci** · 03-23-2009, 17:32

What's the mileage on the vehicle? I wouldn't rule out the PCM unless you have super high mileage or do a lot off off roading in wet or muddy conditions. When was the last tune up performed (especially new plugs)?

I'd replace the throttle position sensor, idle air controller (IAC) and I'd get the mass air sensor checked out for proper operation. If the MAS is toast, the PCM won't know how much fuel/air mix to give the engine for proper operation.

If one or a few of these lower cost fixes solves the problem I suggest getting a transmission service done for better piece of mind.