I recently took my 84 carbureted 350 z28 out for a spin and it was running like total crap but I figured it was because it sat for about 2 months. But, after a while it started running worse and worse until finally I had to peddle it just to keep it going. A friend who was following us informed us that the cat was glowing red hot. Of course I stopped and had the thing towed home. What would cause this? The timing has not been messed with and it ran perfectly before it was parked. No vacuum leaks and distributor hasnt moved. What gives?

 

It's plugged up, get a new one put on or gut it for the time being.

 

but the cat is brand new...less than 10,000 miles on it! Its a catco. Could that still be the problem?

 

If it is glowing red, then you are running way too lean. I would make it richer and see if that fixes the problem, but if it doesnt, then you probably have a plug cat. It doesnt take much when you run the motor too lean

 

if it was running lean enough to make the cat glow red....i'd think it would melt the exhaust manifolds.

i really think the cat is clogged. But since you say it was sitting, theres a possibility some kind of animal crawled up the exhaust and made a nest, plugging things up.

 

Just to be sure, gut the lousy cat. Or, better yet put a strait pipe in for $10 like I did. THen you know for certain if it is the cat or not.