Hello folks,
This van backfires out the intake (once) under moderate to heavy load. It also misses at idle during cold operation. The miss disappears as it warms up. The backfire remains.
I replaced the worn out plugs, wires, cap, rotor and PCV. This improved the idle quality but didn't cure the miss. Idle vacuum increased from 15" to
17".The TPS, MAP, MAT, CTS, Cam Sensor, and Crank Sensor all test within spec. No codes.
The O2 was replaced, cross counts were too few and it ran better with the old one disconnected.
Fuel pressure is rock solid all the time and in spec.
EGR tested ok.
The only other problem I can find is the catalytic converter seems to be rattling/broken up. I don't believe its blocking the exhaust because it passes the vacuum test for plugged exhaust.
What am I missing? Could EGR cause the backfire?
Regards, Brent