I have an odd rattle. When on an incline and brake is depressed fulley there is a rattle that sounds like it is coming from the engine compartment from the right side. When I let off the brake it stops or on level ground.
I have the 2.4 and mtx.
Anybody else have this or any ideas?

 

I don't have an HHR, BUT ... i thought I read on another thread somewhere that when you're on an incline, the automatic trans sort of takes over on its own to relieve pressure on the transmission. On an incline facing uphill, right? You say you have "MTX," not sure what that is. I guess if that means manual transmission, then disregard what I'm saying here.
So, you still might have a problem. I'll keep looking for that thread, I just read it the other day.

 

It does it facing down hill and even while stopped until I let of the brakes. Thanks

 

Here's a shoot in the dark, ABS wheel sensor..let us know what you find out. Good luck.