Thomas55

Stumped here with my 2006 f150 xlt 5.4 3v. 171k Bought the truck from an auction and immediately found the passenger phaser has snapped. So let me start from the get go of what I did.

New heads, phasers, chains, guides, solenoids, and such have all been done.
Oil Pump
Water pump
Coils all checked out
Plugs were like new (regapped them though)
New throttle body (reset computer)
New battery
Cleaned MAF (considering buying new)

Now heres where I'm stumped. At a cold start the 2006 truck runs and drives great no misfires that are truly noticeable my old 2005 f150 had the same tiny misfire and I never paid no mind to it since nothing bad happened.
When the engine is at normal operating temp I will put it in gear or turn my A/C on and the throttle will range down to 300 and then back to 698 according to my datastream on my scan tool. I can drive it around my parking lot with no issues yet when I get on the main roads limp mode will come on. Pull over kill the truck re fire it and wrench is gone and doesn't show me a code on my code reader. What in the ever living lord is happening?!!! Fuel pressure ranges from 38.8-40.2 never goes way over or way under. MAF lb reads between. .61-.88. Note these readings are all taken at an idle

BadFish523

Moved to the 04-08 section. You'll probably get better responses here.

Thomas55

Thanks I really appreciate that!

redfishtd

Never heard a of a self resetting cel not leaving codes . Pcm should have control of all this . I would check my grounds to PCM maybe shes losing power when you are turning off system that would reset her. Or a loose power feed to PCM . Maybe thats why shes acting up all together ,don't know which power fuse keeps memory . PCM has several feeds I'm sure .Low voltage can also do it . Some alternators act up on this engine .
As much work being done on her, grounds may have been left off . Clamp some good grounds in and test her .
How about leaving her running and check for codes when cel is set .
Cats test comes to mind also since she goes bad when you power up .

Thomas55

AFter much headache I finally found a repair shop that could flash my computer for me due to that the ford dealers around my area were 3 weeks out! and now it runs like a champ! Thanks guys!

redfishtd

Was it changed or what . I guess we will never know . A flash is usually an upgrade program unless it got moved from another vehicle . Unless it was flashed by an after market supplier and it got screwed up .

Thomas55

I changed the throttle body and just had it flashed the whole truck is all new to me i bought it sight unseen for a grand.., I'm posing a new thread however though about the phaser dowel snapping on me if I could get insight on that I would appreciate it, I don't believe the wrench light had anything to do with that though due to this issue was what I found when I first tore the truck apart