I searched but didn't really find much advice on fixing the problem. HEre is the situation. The intke side is saturated with gas and carbon. However the exhaust side is clean and white. I have no cel's and I am pretty sure the o2 sensors is working fine sense I pulled it and it was white tipped and has a curve on the scope that goes up and down. Maybe fpr Im a 95 What can I do to check this and or tweek, remove, upgrade to adjustable. Or will retarding the intake side correct this. Guess I got to get a safc! Wont to fix pronto need engine. Oh yeah I sure this is why I am backfiring at high rpm's.

Replace the 02 sensor.