Rattle and Hum
Thread Starter
Intermediate
Joined: Dec 2004
Posts: 27
Likes: 0
Rattle and Hum
My 1989 six speed coupe with 72,000 miles recently had the catalytic converter removed and replaced with a hollowed out stock cat in its place. The reason for this was that the cat was completely blocked. Since then it has run very well, however, I have developed a new problem. After I have driven to a destination, parked the car and have restarted it after an hour or so, there is a discernable rattle or knock coming from the engine or underneath the car. I get a "check engine" light but only briefly. It comes and goes. If I engage the clutch the knock goes away but not completely. The sound may be coming from the connection from the y-pipe to the cat or from the pre-cats. If it sits for a day or so and I drive it again there is no noise. It only happens if and only if I have driven it, stopped and started it again.
