I recently took my 2006 Audi A4 Cabriolet to a well known auto repair shop because my check engine light came on. They replaced the motor mounts and the engine mount stop. I picked up my car and the check engine light came back on 4 days later. I took the car back and they found that the spark plugs needed to be replaced. I just picked my car up 2 days ago and my check engine light came on again today. Could there be a glitch in the dash that keeps triggering the CEL or is this a bad mechanic who is not fully inspecting my car?