My questions is what is causing my car to stuble when boost hits 0 psi?

The history:

Car is running pefectly. Almost all stock, but a fuel smell comes in the cabin at idle or at a stop light. The facts point to a bad FPD on the primary rail. I take a look and this seems to be no small task, but I built a motor and put it in so I wasn't too intimidated. Ordered the part from Ray. FPD was definately bad. Pool of gas sitting in crevice between LIM and block. *WARNING*

Changed the FPD out, and it was a lot of work. Afterwards downpipe always started to glow at startup. About a week later, another fuel smell arose. I tore into it last night. After running the car, I could hear a noise under the UIM. I figured it would be easy to troubleshoot. Once disassembled, I could see fuel leaking around the top of one of the primary injetors. I had new o-rings, so I pulled it all down again to change the o-rings... Advice: Change it all at once !!! Actually, I was screwing around with the injector when I had it out the first time, so I think this is why it leaked... Be warned. Used the F/P diagnostic terminal to check for leaks this time...smarter/older/wiser...

Analysis: When an injector o-ring is compromised, it can leak up/out and down (there are two). This not only was leaking on top, but leaking into the engine. A lot of unburnt fuel was going out the exhaust pipe and burning in the exhaust. It did show up in the fuel mileage also, which dropped below 15 around town.

Got it all back together and car starts and sounds perfect. Idles perfect. Vacuum is a couple inches too low. It sits about 15 and normally is 18 to 20. Took it on the street for a little ways and the car stumbles when hitting 0 psi on the boost gage. I have been back over it with nothing obviously out of place. I need some suggestions. I am sure something is not put back right again...I am wondering if I have a severe vacuum leak that is not allowing boost to build. Also, with the car running insanely rich before, do I need to reset the ECU?

 

What, no comments at all?

 

Sounds like limp mode. I would reset the ECU and then try it again. If you still have the the problem, pull the codes.

 

Oh, I never thought of that. I turned the key on several times while it was torn down to operate the fuel pump and check for leaks...

That could be it ...thanks...