2004 exhaust rattle

Last November the ICM went out on my cavalier. We replaced the plugs first, and when that didn't help we put in a used ICM. After about 30 days, the ICM failed and we put another used one. This repeated 2 more times, with the ICM lasting about 30 days each time.

This morning the ICM failed again. I found some posts here advising against the Bosch plugs that I had put in, so we replaced them with OEM and installed a new ICM. Now the exhaust seems to rattle a lot. Each time I had to drive it with the ICM out it rattled, but it went away after the part was replaced. The exhaust appears to be hanging down a lot lower than it used to. Is this related to the ICM problems?

I would appreciate any pointers that someone can give. I really want to get this problem resolved as this car is my only transportation.

Thanks!

Hello fellow New Yorker...

The exhaust rattle is irrelevant to the Ignition control module.

Bosch anything on a GM car is a bad idea. O2 sensors and plugs.

There are a couple bolts/nuts holding the exhaust manifold heat shield to the motor, i'd check those out to make sure they are tight.

Can you be a little more specific as to where the exhaust rattle is coming from if its not up by the motor?

I have spent the last couple of days listening to it during my commute. I think that I was wrong to call it a rattle. It usually has a low, grumbly noise when I am accelerating. the noise sounds like it is coming from underneath the car. Where are the exhaust mounts on this vehicle? I'm trying to figure out why it looks like it is hanging down so low. It scrapes on rough road much more than it used to.

The muffler hanger is a very weak point. There is a rubber isolator block bolted to the "frame" just inside the LR wheel, they fail a lot. I just replaced mine on my '04 today(only 83,xxx miles), it cost about $10. There is also a rubber hanger just in front of the rear axle. There's probably one or two more, but I had a pretty bad hangover and wasn't really looking for more work :)

It seems that the ICM going out had caused my catalytic converter to die. I got the cat and everything behind it replaced, and now the exhaust system doesn't hang down and all of the rattly/grumbly noises are gone.

Thanks for all of your help!