car is messed up

some people say my catty converter is cloged. i dont know what is wrong with it.. it is a 98 grand amgt 2.4 liter twin overhead cam and the catty converter is getting red hot and my exahust is shaking...and..my car sounds like a lawnmower. at first it wouldnt start but i changed the spark plugs and now...it does..but it stillhas the above problems. what is wrong with it?

o ya..i almost forgot...i had a cold air intake on it but i did not pull the card from the ecu to change my air/fuel ratio...could that be the problem?

Your converter is glowing because its burning fuel inside it. Yup, you need a new converter. Did this problem happen after you installed the cai? If so, you will need to get a chip burned for your car that alters the fuel/air mixture, ask ridenour about that he seems to be the one to ask. If it was doing that before the cai, then you had a problem to begin with, check your o2 sensor, maf, and air filter.