so for some reason my car keeps dropping into what seems like a limp mode but no check engine light comes on. it did it a couple weeks back and i disconnected the battery for 5 min. and it fixed it, but not tonight. i was wondering if maybe it has something to do with me putting an aftermarket head unit in the car, seeing as how i didn't have any trouble with it before the head unit was in. ( it also has APR 93 tune if that matters). any help would be greatly appreciated.