Well I replaced my Pre-Cat O2 as you suggested HeyYou...but my bad idle is back...it was fine for a few days. I pulled the new Pre-cat O2 and its still shiny new.

Just to re-iterate.. From cold start, truck runs fine for 1-2 mins, then starts to idle real crappy for a few minutes, then eventually settles down on its own.

Cat is new, Plenum fixed, Brand new O2 sensors pre, and post.

have taken the TB off and thoroughly cleaned it.

new plugs and wires

Brand new IAC.

Only thing I haven't replaced is the TPS...but cant really see how that would effect my idle...

 

ya tps i would try and go form there what brand o2 did you go with and how much did it cost ?

 

Ndk, 90$

 

Well, that's a quality part...... Wonder what the heck is going on there. If you unplug, and drive without it, does the problem go away? Did you reset the pcm after you changed it??

 

Could also be ECT sensor.

 

problems still there without the O2 plugged in.

I had the neg battery cable unplugged the whole time I was changing the sensor, for good measure though I also turned on the headlights and cranked it to start for 10 seconds with it unplugged to make sure I got out any residual charge...so yes, I reset the PCM...

 

Interesting...... Have you cleaned your throttle body/IAC motor??

 

Yes, my IAC is brand new, 2 weeks old. when I replaced it it had no effect on the problem at all.

Yes, Ive pulled the TB and removed every spec of dirt possible.

 

Ok, this one's a real reach, but, what about fuel pressure?

 

I could check....but I really don't think its that, my idle is fine and stable 98% of the time, it runs great, good power...Its just for that minute or 2 after it slides off fast idle after a cold start that it runs like crap..