Thread: Really rough idling and choking on acceleration.

Originally Posted by scottydoggs

could be a clogged cat, reach under the car and bang on the cat, if it makes noise like stuff's bouncing around in there its dead. also at night drive it around for a bit and see if the cat is glowing red, if so its shot. and you could pull the o2 sensor out and drive it, see if it is better, yes this will cause an exhaust leak but if it runs better you have a bad cat.

Can you tell me which o2 sensor to pull? I have the same problem and think it may be the cat. Is it the one after the cat or before the cat. Also, do I need to pull the sensor out, or can I just disconnect the wiring harness for the test?