Ok guys, It's now officially driving me crazy, My car hunts up and down, after engine is at operating temp. When coming to stop, it shuts off.. I have replaced the maf, repalced the map, I dont know where to go now.. It runs rich at idle, runs lean at wot..
When the engine is cold it runs great, Once warm it starts all the trouble, I am a good mechanic.. But the damn thing wont throw any Service engine codes. I have reocated my bypass hose for my charger, I have good fuel presure, 40-42 psi at idle.. The o2's seem to be working ok.. When you stop at a light after the engine is warm and you try to keep it running, you have to feather the gas and it acts like its loading up..I have new 30# accell injectors, this problem started after the superchrger install.. I have no cats,no emissions..Should I move my maf to the blow though side of the air system???. I have a bigger cam, msd ignition, 1.6 rr's, dual fuel pumps (one push one pull).All forged internals.. bored to a 355.. I have disconnected the fmu to make sure it wasnt the culprit, I am soon to unhook the charger and see if the problem goes away.. these syntoms startd before all my mods.. I hope someone has seen something of this nature.. Please throw me some advice..
I miss having my car.. Need help.. thanks..

 

Sounds like something related to the IAC. Or opti problem.

 

Well If the iac was stuck, would it show to be moving correctly in the logger ie.. 30% 40%? Also, is the iac supposed to be moving once your foot is on the gas, I kinda thought it should be at zero once the throttle plate moves?
If it were the opti why wouldn't it do it all the time, it runs great until the engine gets warm.Maybe a break-down in the electrical? Thanks for the advice..

 

Yeah this one is a difficult one that for sure. You may want to move this over to another furom. Like LT1 you may get a better reasponce.

 

A scanner only shows you the IAC positon the PCM is commanding.... there is no feedback to show where the IAC motor actual is positioned. The "position" is in "counts"..... 0-255. 20-40 counts is fairly normal at idle for an N/A engine. If it was "stuck" it would just cause the computer to keep commanding it to move, and the PCM would eventually max it out at one extreme or the other.

Once you start to open the throttle, the IAC will start to open up more, reaching 70-90 (or even a little more) on an N/A engine. This prevents the engine from stalling if the throttle blades close suddenly.

Check your TPS sensor... if that isn't returning to 0.90V or less at closed throttle, it will confuse the PCM and it will try to hold elevated engine rpm's until it senses the throttle is fully closed.