Clogged Cat?

[Sircnay]

What could conceiveably happen if you have a clogged cat?

Also, My car's got a rough idle. Wasn't like this before. Redtop 93 SR20DET. it'll bounce around from 1000 to 800 but stutter almost and blow tiny tiny clouds of black smoke while it's idling. Sometimes it'll idle fine and sometimes it won't I'm so friggin pissed at my car right now... Anybody know what's wrong? I"m thinking a clogged Cat? or possibly misfiring sparkies? Or something worse?

[S13240]

I know from personal experience on all tracs that clogged cats cause red turbos and manifolds

[RobDET]

sounds electrical. Could be the injector O rings too. Check the ignitor resistance as per the service manual. Also make sure you are getting good ground and voltage to the injectors. They have those little lights you can test them with.

[Sircnay]

Fixed it. Turned out to be really really really old fuel filter and sparkies. *sigh* I hope that all my car troubles are this simple to fix.