Supercharged 03 Mustang Gt Surging Idle After Hard On The Throttle

[blowngt03]

Okay this has been driving me crazy and Iv been dealing with it for about a year now. I know there are tons of threads kinda like this but nothing is working.

The car is a 03 gt 2v with a saleen supercharger. Basically a m90 supercharger. Its basically stock besides all the components to work with the supercharger (injectors/fuel pump etc)

If I baby the car it runs/idles okay, not perfect but okay. Now say I go out on the highway and beat on it as soon as I slow down it will hardly stay running at an idle. When I come to a stop it has a really high idle (stays around 1800 rpm for about 25 seconds) and then it drops and starts surging bad (jumps from 200 rpm to around 1100 constantly) when I take off and cruise around certain speeds the car starts bucking really bad. And it will stay running like this for weeks.
Iv replaced the o2 sensors, cleaned the maf, cleaned iac, and tryed a few other things. No leaks anywhere.

I found a thread that someone said to go on the highway and go to 65 mph and keep it in 5th gear and decelerate to 35 mph a couple times in a row and it will relearn the tune or something. Well I tryed that and and I can't believe it but it actually worked. It will go from surging/dieing to running smooth as can be. And as soon as you beat on it again it runs like crap again

Does any one know why this is happening? I have to baby the car at all times unless I want it surging/bucking/high idle. Atleast I know a temporary fix but no one can figure out why it does this.

I had the car for 2 years and for the first year it ran perfect and out of no where this started happening.

 

[Noobz347]

Codes... What are they?


You have something pushing your EEC out of closed loop at operating temp. Should be able to pull a code that will help you diagnose.

 

[blowngt03]

Haven't checked latly but ill do it when I can use my buddy's scanner. It doesn't matter if its at operating temp or cold it basically runs like a car with a huge cam barely running. Not long before this started happening my alternator went out and left me stranded. Think that could have anything to do with it? Also my fuel pump went out the day I bought the car and he ended up putting a cheap one in, considering im running a supercharger and bigger injectors do you think I need a higher flowing fuel pump?

 

[Noobz347]

Haven't checked latly but ill do it when I can use my buddy's scanner. It doesn't matter if its at operating temp or cold it basically runs like a car with a huge cam barely running. Not long before this started happening my alternator went out and left me stranded. Think that could have anything to do with it? Also my fuel pump went out the day I bought the car and he ended up putting a cheap one in, considering im running a supercharger and bigger injectors do you think I need a higher flowing fuel pump?

If you suspect the fuel pump then change it. I've stopped second guessing fuel pumps. They can be brand new and take a crap. I could probably fill a page with the number of weird issues that have been resolved by replacing a fuel pump.

You should still however, pull those codes. If you have a pump issue then you should see error codes for 02 sensors and you should have a check-engine light.

All bets are off if your car has been tuned and the things have been disabled or turned off.

Have you completely reset your EEC at any time?


Edit:

Oh... If you're running any off-the-shelf "Performance Chip", pull it and stomp vigorously with boot heel.

 

[blowngt03]

I always have a code running lean on bank 2 I remember we changed the front 02 and I don't have any back ones I have an aft mounted in the back (that don't work) and a bung. And what do you mean reset the eec? How do I do that? And my traction control is disabled so im guessing a shop tuned it but I don't have any chips or handheld

Thanks alot for helping man.
thanks for

 

[blowngt03]

Alright I checked my codes. P0135, p0155 (upstream heated oxygen sensor)
P1131, p1133, p1150, p1151
Manufacturing control fuel air metering

 

[84Ttop]

Have pictures of this setup? It sounds as if you may have a stuck or sticking IAC and I don't know where it is placed on the saleen blower setups.