they will know what to do, but basically scan for engine fault codes. you could have a knock sensor gone down. any pinking and the ecu will retard the timing. in fact , to optimise performance it keeps the timing roughly at the point where its just not pinking. old cars with distributors did this with bob weights pretty well, but an ecu does it more complicated. if your problem is pinking, then it does sound like something is wrong electronically.