About a month or so ago, I started having a problem that when I would turn on heater, roll down window, etc, my car would jerk, and the rpms would go down, some of my dash lights would come on, but then it would go right back to normal. Took it to the dealer, and had them put it on the machine, they said they were 75% sure that it was the belt and/or the belt tensioner. Boyfriend replaced both and didn't seem to have the problem any more. Just yesterday, I started having pretty much the same problem, almost every time I would put on the brakes, roll down my windows, use turn signals, turn on heater, etc. it would do the same thing. My brother asked around and everyone said the same thing, that it sounds like my computer. How can I find out for sure and how much could that cost me? Any advice would be appreciated.