Weird issue, hopefully someone can help me out....

This has now happened to me twice in the past few thousand miles...

1st time, I was circling in a parking lot look for a space, stopped, put it in reverse and the engine began stuttering, gave it a little gas...drove around a bit and the stutter wouldn't go away. I turned the truck off, restarted and it was back to normal...

Today I pulled into the driveway at work and it immediately started this same issue...turned it off and restarted, problem went away...

After the first experience I went to Ford, changed the spark plugs, injectors cleaned, and replaced the fuel filter....obviously those items aren't the issue. There hasn't been a check engine light at all

Any ideas?

 

Did you check your O2 sensors? I had a (God forgive me) Pontiac van years ago which did the sam thing- almost to the point of stalling. No codes were set but the dealership found a bed O2 sensor. that is what is very well could be. If you connect a scan tool and view the real time operation of the engine the O2 readings should change quickly from .1-.9 volts. The secondary may move a little slower.

 

Thank you for the reply...usually the O2 sensors are on the exhaust manifold...is that the case on the 04-08 F150's? I'm guessing I would need two of them?

 

On the 5.4 there are 4. 2 pre-cat and 2 post cat. The 2 pre cat sensors are the ones that affect engine operation. The 2 after the cats are only monitoring cat efficiency. It is usually recommended to stick with Motorcraft sensors which I believe are made by Bosch. roughly $50 a piece.

Your problem could also be a COP but without a code it would be hard to tell which one.

 

On my 08 I found all 4 O2's easily, the problem being the darn wires on the passenger side run over the tranny to the drivers side, PITA to get to...the O2's themselves will be easy to remove from the pipe

I noticed the O2 on the passanger side before the CAT had moisture leaking from it...probably condensation after cooling off...could this be the issue?

 

Slightest leak could cause problems. The O2 sensor compares the amount oxygen content in the exhaust to the oxygen content in the outside air. A leak would confuse the O2 sensor- making it think that there is more oxygen in the exhaust than there really is.

 

The pass side is a pain to change. I just did mine last night. Actually 7/8 open end wrench worked good for breaking it loose. You have to bend the heat shield on the cats to get your hand up there. I actually took the down stream sensor out on the pass side to give me a little bit more room to get my hand up there.

 

i never really realized this..
a leak in my exhaust somewhere around the O2 sensors could so adversely affect my truck performance. i have a couple small holes i know about that moisture leaks from.. i should get those fixed!