I have codes p0404 p0300 p1181 I have loss of power at 2000 rpm. It has203,000mi on 2002 Pontiac Grand Prix

I am planning to replace the cat, but I can hear a sound like an exhaust tip from the air filter housing. Can a restricted cat cause this?

by in Manassa, CO on August 15, 2011
1 answer
ANSWER by on August 15, 2011
If the exhaust is backing up and not being allowed to exit the engine it will force its way some where and when the intake valve opens it will try to push into the intake but at that stage the exhaust would glow red and would stall after a short period of running. Undo the down pipe to cat converter flange and start the engine see if it will now rev up once the restricted exhaust has been removed,