Backfiring??
 

What would cause it to backfire on WOT 1-2 & 2-3 shifts?
I dont't think I have any exhuast or intake leaks, how can these be checked for? None audiable.

Re: Backfiring??
 

At what RPM ? Maybe you're floating the valves ?

Re: Backfiring??
 

If you have the air injection reactor (air pump) system still on your car, replace the one-way check valves and check to see that the diverter and atmospheric dump valves are operating and properly connected. That or you're getting air introduced into the exhaust where and/or when it shouldn't be.

On the other hand, if you're leaning out, you need to check the fuel pressure while on a WOT run.

Hope this helps. :)

Re: Backfiring??
 

It does it when I powershift at 5200-5400RPM.
Smog stuff all gone.
Have pressure guage on shrader valve. Adjustable FPR set at 40psi.
190lph pump

Re: Backfiring??
 

I replaced blown header gasket, found a bad wire.
Backfiring much less, but still once out of eight or ten shifts, ecespecially on the spray (60 shot)