Chevrolet: Rough Idle on Cavalier, chevy cavalier z24, 1997 chevy cavalier

Question
Hi Harold.  My name is Amy. I have a 1997 Chevy Cavalier Z24 with 2.4L engine.  Recently (past few months) I have noticed a very rough idle.. or strong shaking in my car.  Mostly while at stops or in park, and seems to happen much more often..if not totally while the air conditioning is on. I've noticed that at the same times my car shakes the rpms on my techometer drop in sync.  I thought it could be a loose wire on a spark plug or something, but couldn't find them easily to check. Would appreciate any ideas you might have. Thank you.

Answer
The most common problem is a partially clogged injector. They should be cleaned about once a year. Also the coil housing is known for shorting out between cylinders on your engine. The reason that its worse with the AC on is because the AC compressor is adding a load to the engine. You should probably take it to the shop and have it diagnosed soon before the misfire damages the catalytic converter.