throttle by wire means voltage is sent to the throttle body...so where there's an electrical connection, there can be a short, loose wire, loose connection...but since it doesn't do this all the time, the throttle reset may work...if it doesn't, then move the peddle around, making sure it hasn't come loose or out of alignment in some way...the car has a natural hesitation, but not 5 or 10 seconds....good luck