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Hello. I recently noticed that there is about a second delay after i turn off my car and then the needles seem to move back and forth, about half an inch, very fast for about a second. Also along with this almost shaking of the needles is a quiet buzz sound. It started with all the needles, and now any number or combination of needles does this at one time. This only happens when i turn off my car and the only mod i have on my car is an amp powering two subs, which ive had for two years with no problem. Anyone know what this problem could be? thanks in advance.