MTX ground issue

I suppose I should have also mentioned that back when I had the other 4 channel amplifier powering the other speakers, I, quite idiotically, touched the speaker wires from the 4 channel amp to the chassis of the vehicle when my system was on. This is when the problem started. Since then I have replaced the amp, installed a new higher quality amp kit, and had the preouts on my receiver replaced, but still the problem persists. Also, my car is a 2004 Oldsmobile Alero and when I had the 4-channel amp installed I had big alternator noise problems, which I think was due mostly to a ground loop. Does anyone have any idea if that particular car has inherent grounding problems and if so any remedies?

So I guess no has anymore ideas??

i have an mtx 8100d mono block amp and it had the same prob it is the groundin where are u currently groundin the amps, i suggest a seat belt bolt as a good point or otherwise sand back a little paint to ensure good contact, also make sure to run a large gauge wire for grounding as the mtx needs it

to Darth_Soul, try removing the cap, just bypass the cap and run the amp straight in and see if that changes the problem. Also if possible, try anoter head unit, just to remove the Pioneer as a possible, you said you had the pre-outs replaced in the Pioneer but I have found that most unit repairs are not completed very well... mrhifimrsound

Well, 30xbigboy, I currently have it grounded to a seat belt bolt and I did also remove the paint from the surface of the body. I am using 4awg power and ground wire, which should be plenty big enough because in the owner's manual it said that 8awg would be adequate. Regarding your post mrhifirmsound, I have already tried bypassing the capacitor with no luck. I'll admit that I didn't remove the cap ground (grounded at the same point as the amp) when I did this, but I don't know if this would have mattered or not. As far as trying another head unit, well, unfortunately that is not financially feasible for me at the time. Thank you for the suggestions guys.