i am an old 5.0 guy. i have owned about 8 or 9 of these. okay, here it is. my 03 gt already had flowmasters and jba shorty headers with the stock h pipe. i added a mac with mil eliminators off road and now i am having a pinging prob in first and second gear. when in higher gears at wot the prob is not there....it really happens under wot in lower rpms in first gear and transfers into the sencond gear shift then it is gone ??? maybe it is real lean in the first two gears? i am running 93 octane with no timing adjuster. i just decided to reset the computer after adding the h pipe???????????????