Hey guys I have an 86 gxl with a s5 turbo2 swap with exhaust fuel pump(aem) new plugs and wires upgraded top mount intercooler fuel pressure regulator. as the title states when the car is up to operating temp it idles very lean ranging from 14.5-16 however when I start driving the air/fuel jumps down to 12 under mild throttle, when the car gets to the point where it's about to come into boost the air/fuel goes into the 9s(I don't go into often since this problem) I've changed the MAF because mine is on a tilt I was told this would damage it. My fuel pressure is set at 40. Has anyone had anything like this happen to them? Can it be a vacuum leak? Although Ive checked for vacuum leaks .What should I be looking for here? Any help is appreciated. Thanks

 

Let me guess, this is on a stock ECU.

Has the car ever run correctly?

 

As of now yes it's on a stock Turbo ecu. The did run fine for a few months. Under boost(7lbs) the air/fuel would be mid 10s.cruising would be a bit lean

 

vacuum/boost leak

 

I'll check again for any leaks

 

If you have the air pump installed, that seems normal.

 

No airpump. It was removed