pmc203

2002 f150 screw 2wd 5.4l.
Had a cracked manifold, leaked coolant. mechanic replaced with Dorman immediately. (no Codes at all now or then)
Now i have a bunch of weird issues. replaced IAC but has no affect.
These are all things that didnt happen before intake replacement.

= On startup idle zooms to like 1500 rpm, stays there for 5-10 seconds then slowely comes down to about 1000, sits there for a few seconds then comes down to around 700. doesnt matter if its warm or cold. Does this at any point when in park and rev the throttle.
= Having idle hunting between 1000 - 600 when turning on the defrost/heat....all settings except floor. took out a/c clutch fuse, didnt seem to help, still jumps around alot.
= Now i noticed the shifting is really soft....and inconsistant. also when hit the pedal to pass the truck revs fast then downshifts hard then shifts back up again. weird.

This truck has never done any of this and was a perfect driver before. Can anyone offer up suggestions for diagnosis. Thanks!

techrep

iTrader: (1)

clean throttle body and throttle position sensor.. double check vacuum lines.. may have a cracked line after removal and install of new manifold

pmc203

throttle body was cleaned when manifold was replaced.
Does anyone know if there ar any extra ports or anything on the Dorman manifold being different from the stock....something that needs plugged or something?
Thanks

techrep

iTrader: (1)

you didn’t look ... should be the same. The one I installed was identical. sounds like either TPS / IAC or a vacuum leak. who cleaned the TB ??

Blckwlf

I'm assuming they disconnected the battery? If so maybe it needs to complete is testing and calibration process, usually about 100 miles for things to return to "normal".

pmc203

@ techrep - I had a mechanic do the work, and he cleaned the throttle body. I am just fishing for things to check out myself, not knowing that much about Fords, before I run it back to him next week. So the Dorman is identical to stock? I replaced the IAC.
@Blckwlf - yes the battery was disconnected..... is it common to have all these wonky issues with the idle and shifting during the relearning process?
Thanks

Blckwlf

Mines usually weird for about 100 miles during the relearn.

JCR 56

A failing TPS can sometimes cause shifting issues.

pmc203

Well, heres an update. I had a new TPS put on. That cured the weird idle hunting issue and the shifting thing... however it is still revving to about 2000 rpm when i start it up. cold or hot. and it comes down slow.
Mechanic said maybe i need to put on a better IAC. The one I got was from AZ. He said maybe napa or motorcraft.
Any other thoughts?
Thanks!

TNSean

The plastic piece that attaches on the back of the intake for the PVC hose requires an O-ring to seal it up. There should of been one included with the intake. The O-ring goes between the plastic piece and the manifold.

Without this O-ring you will have a massive vacuum leak.