Im having a backfiring problem through the intake. It only seems to happen when the car is in closed loop. I can run it fine with a o2 sensor unplugged (although its a little sluggish) but when it goes into closed loop and I mash on it or just try to rev it it'll spit back out of the intake. I didn't know if anyone could give me a hand on where to start looking in the tuning file. I'm using tuner cat..

Car specs
94 z28
Le3 heads, le2 cam (23x/23x about .600 lift), 37lb injectors (racetronix).. Anything else you need to know? so far i've changed just the injector size by the calculation I found on here somewhere, and I'm turned somethings off to keep the computer for checking things, but I'm not sure where I should be looking for the backfire problem.

Thanks in adv!

 

exhaust?

 

If you mean what I have, I'm running kooks 1.75 stepped race longtubes, hooked back into the stock catback