fstfrd00

2006 4x4 5.4 180,000 miles
I have replaced the plugs, the COPs, the MAF sensor yet I still get a rough idle and a P0113 code (a minus 40 reading with both the old and new MAF). I have a throttle body (upon cleaning mine, I think I messed up the butterfly valve by scrubbing it with carb cleaner) coming today or tomorrow but don't know if I'm going down the right path to troubleshoot my truck. I had thoughts it was the wiring harness but dont know how to check it, or the PCM but again dont know how to check it.
A little backstory.
Changed the plugs but one broke off (The #5 Cylinder)and the porcelain fell in the head. I DID NOT START THE TRUCK AT THIS POINT. I took off the head, retrieved the porcelain, double checked timing, re-installed everything with new gaskets, hooked all the sensors back-up. Has had a rough idle, wrench light and p0113 code.
Saturday I ran into town to do an errand. Upon getting back in the truck to leave, it had trouble starting then proceeded to die at an intersection. After a few hours of tinkering it started right up, still running rough but didn't die as I got it home.

I have searched but couldnt find anything to help.
Please help....

biggdaddyp

PO113 indicates an open circuit, since you have already replaced the MAF I would look at the harness for an open somewhere i.e. cut wire, pinched wire, bent terminal, terminal backed out of connector.

fstfrd00

I will check that when I get home from work and will update the thread.

Mod (Ret.)

The only thing you may have done using carb cleaner instead of throttle body cleaner is to have removed the protective finish on the throttle plate/butterfly, so the carbon may build up faster on it, and require more frequent cleaning.

fstfrd00

Now I know. At least I can return the TB I bought.

fstfrd00

I followed the harness to the back of the intake manifold (as far as my arms will allow) and didn't find any pinched wires. I checked all connectors on the top of the engine for broken wires, backed out connectors and bent terminals = nothing. Any other ideas?

fstfrd00

I will be taking it to the dealer this weekend and will update the post with what the dealership finds.

fstfrd00

Ok, have not taken it to a dealer yet but father in law wanted one last look before. Well when checking the harness I stop short of the PCM. Well a plug was slightly backed out on the PCM. :O now it is running smooth.
One plug was already fouled from all the misfires, we replaced it.

bourgeois1269

Hopefully that was the culprit but NEVER take it to a STEALERSHIP unless your still under warranty because they will find more problems to make more money. I spent $1200 at ford one time and my truck still didn't run right but after I took it to a local mechanic and paid 1/3 of that I've been OOOO-TAY and that was close to 1.5 years ago