Bought a 98OB last week, 2.2 5speed w/ 170k on it. Runs like a bear, but had a slight exhaust leak when i bought it, i got a great deal so i didnt care. Today, i noticed some slight power loss on the highway, and when i got off the exit, the whole car was shaking and hesitating. It never stalled out and has no CELs. My thoughts are that the cat is shot and causing it to perform like this. I have not gotten a chance to get underneath it, and i am just going to take it to my guy to get it done. Anyone ever had this happen and can confirm that it is indeed my cat that is shot? TIA!

Lot of the OBDII programs will let you see the O2 sensors and their response. The sensors should be changing between 0.5 and 0.9 volts, rapidly.

 

If the cat is blocked you would most likely have a CEL. Is the CEL on? A blocked CAT will not go away. You could always drop the cat and see if the problem goes away, but it will be very loud.

i just went out and fired it up..the check engine light does not even come on before starting for the bulb test, so either a: it is burned out, or b: someone disconnected it. We will start out scanning for any codes then drop the cat. stay tuned.