Serious car audio problem.

I started upgrading my car stereo equipment in my 96 gst that had a factory infinity system.

First I installed my sony xplod bluetooth stereo. All speakers worked great, no issues. I used the metra install cable so I didn't have to hack the factory wiring.

I bought a kenwood 4 channel amp from my boss for 40 bucks, this is where the problems happen. I used 4 gauge wire from the battery, grounded with a 4 gauge wire under the passenger seat. I spliced into the factory amp wire harness for the speakers wires. I have the tweeters on the same channels as the front speakers. I have lightning audio 4 channel rcas. Remote wire is ran right as well. When I start my car, the stereo says failure, and I hear a slight buzz coming from what seems every speaker. Sound is better than it was, but I hear some distortion at a higher volume. When I turn the car off, an obnoxious buzz from one rear speaker and the front right tweeter/door speaker. I put my mb quart speakers in the doors, and that didn't change anything. I checked the wiring 3 times now and I am stumped. All I changed was I installed an amp. I also smell a faint burning smell, but it could be because the amp is under the passenger seat and its getting warm.

any help appreciated.

where are you taking the remote signal for the amp from? unhook all speakers from the amp and hook them up one by one and test that it works or doesn't work. also make sure you have a clean ground.

the remote for the amp is coming from the remote wire on the metra install harness. i made sure today the ground for the amp was clean. I should also add, on the way home today i was playing music, then all of a sudden there was no sound for about 5 minutes, then sound again.

if it all worked prior to the amp install then all issues lead back to that. Do you have a pair of cross overs for the front speakers?