[PaulD]

DC offset in the amp means the amp is bad .... that may actually be the problem but not if it works in another vehicle. I agree, it can be frustrating when the answer is not obvious and you just want some tunes. This is very strange and might be difficult to troubleshoot over the internet. There is something I am just missing and not really sure what it is.

Do you have a volt meter in the car, like on the dash instrumentation anywhere ? It could be that the bigger amp is drawing a lot more power than the smaller one. Have you tried the gorilla amp with the gain setting all the way down and no bass boost ?