I have a 1997 crv that had a bad head, i swapped out the head with an ls head obd2 and changed the timing belt water pump ect. The problem is that it backfires through the intake manifold while driving and I am at a loss to know how to fix it. The car does not backfire while not driving even while in place and revving the engine it does not backfire. It only backfires when under load, generally more when cold and occasionally when warmed up. This is what i have tried so far
- new cap, rotor, and wires
- checked for vacuum leaks and there were none
- used seafoam to clean injectors
- checked and rechecked ignition timing
- no cels

Does anyone have any ideas, i have searched and cant seem to find this problem i am having. The car also passed emissions with the problem, if you have any ideas please let me know

Thanks Travis

 

Try replacing your spark plugs

 

try putting the DISTRIBUTER back in time correctly with a timing gun.