My car sometimes runs lean from a dead stop...sometimes so lean the car pretty much completly bogs out and backfires. Once I get into boost it runs fine and the afr are where they should be. When Im rolling down the road its not a problem either I can put the foot to the floor and it runs fine afrs are where they should be. It sometimes goes lean in between shifts too and I dont remember that happening. What could be the cause of this issue? Could it be tune related or something mechanical? I havent changed anything since April when I got tuned.

 

How many kms on the car? It could be a sticky injector, try some injector cleaner.

 

Im right under 40k miles.

 

You could also have an exhaust leak before the WB sensor.

 

Why would a leak before my 02 sensor for my wideband make my car stumble. Its not just showing high afrs on my wideband its running ****ty from a dead stop. Like I said though it runs fine when Im not going from a dead stop.