Kinda weird how this went down...
so I pick my car up from the exhaust shop and it runs fine I drove it 5 miles to a friends then 5 more miles to my grandmas then 10 miles to my inlaws then at some point between there and the store it started running like @!#$. The cell came on so I got it home and checked it. It says bank 1 too lean. If I keep it out of boost I have no issues at all, though it takes a few cranks to start... any input? It has used gmpp injectors, used tmap, walbro 255, and a reflash ecu which I bought from someone on here.

It also seems like the boost shoots up to quickly. Like at 20% throttle I'm seeing boost. So I have to take off really easy and feather the gas until it relieves pressure

more info on the exhaust you had put on

downpipe, slp high flow cat, s*rs cat-back, all 2.5" pipe. The downpipe is a little @!#$ though its bent funny so it might be restrictive a little, but I had no issues at first. But on the flange the guy put a section of bent pipe to avoid the coolant line and its kinda crushed a bit

I'd unplug the battery for 15 minutes then see what happens after that, let it run through for a while. I don't run a cat on my car, just to avoid problems like that...

I reset the code with my scanner already. Then it popped back up after about a mile of driving and same problem.

my guess is you have a @!#$ty tune. as far as the turbo spooling quickly. what turbo is it?

Start with all your vacuum, check it all, that can cause boost and running like crap. Make sure they didn't knock anything around or change anything messing with the car while you were gone...kinda why I am always in the bay with the exhaust shop guys

Check your MAP sensor or the wires going to it. I recently had this issue and had a faulty Map sensor wire on the harness side. Also first O2 on my car was bad.


1999 - Cavalier - 5speed - Exhaust - 17" rims - carbon fiber hood - the beater

Thanks for all the advise. After reading here and speaking to the guy at highflowfuels.com I am led to believe the venturi valve is bad on the fuel pump. I am going to check my vacuum today just for giggles but I am 90% certain it is a faulty fuel pump. Turbo is a td04

checked the fuel pressure and it stays around 18 constantly. start up, wot, vacuum and boost no matter where the throttle is it stays at 18psi. the venturi valve is bad so hopefully they will refund my money so i can buy the racetronix as opposed to sending me another pump that will fail...

you said you have a walbro 255 just get them to give you a new one the racetronix pump is a walbro 255



JBO since July 30, 2001

Racetronix unit is installed, now seeing about 45 at idle, 50 while cruising and 40 under boost