Engine Bad Iacv?? Or What?????

[thatone1320copcar]

Ok so ive been having alot of issues with my gt recently, she was running really good after i swapped my upper plenum for a ported and polished crown vic plenum. Then after about 100 miles of driving it started running really rough and threw codes for lean bank 1 and 2, insufficient egr flow, and it felt like a misfire..... i remember reading a thread a while back and after the guys plenum swap his iacv went bad, and a few others had the same issue. Could that be plausible for this situation? Replaced plug wires, swapped around injectors, new dpfe, new lower manifold, new screamin demon coil packs, im stuck. When pulling plug wires 1,2, and 6 off the coil pack theres no change in idle and it runs really rough. Any help would be greatly appreciated. Oh and car is a 97 auto gt with 144k miles

 

[wmburns]

A bad IAC valve isn't going to cause a lean DTC code. My vote is there's a vacuum leak. Since you have installed a PI intake on a non-PI heads there's some additional sealing steps needed. If this were me that's where I would start.

Here's some more information on how to trouble shoot IAC/Idle issues:
http://www.stangnet.com/mustang-forums/resources/troubleshoot-iac-idle-problems-1996-2004.13/

 

[thatone1320copcar]

Car ran the same on npi manifold and i rtved the entire gasket doubt theres a leak there. And ive sprayed down the enite motor basically with carb cleaner and it does not raise idle at all. Its weird how just those 3 cylinders dont make a difference if they are plugged in or not