I
immigrant song
Guest
My 1993 Buick Skylark 3.3 V6 will start and run for about 10 minutes (usually quite well but sometimes misfiring) then the cat starts to glow red and the skipping gets worse and then the car cuts out and will not re-start for a long time (usually a couple of hours). I have replaced the o2 sensor and the CTS, I obtained a used ignition module from a junkyard and have a new crank sensor to install. (not done it yet because i cannot lock up the engine to stop it rotating when removing the pulley bolt. Which brings me to my question, we have a chicken/egg scenario, is the mis-fire causing the cat to glow from more unburnt fuel being oxidized inside than normal HC levels dictate or is the glowing cat blocked and causing the misfire due to back pressure? I know that the misfire has caused the primary monolith inside the cat to be burned away by the unburnt fuel. but to solve this quandary, I need to rectify the source before replacing the cat. I hope you can help me and thank you for your time.