hi i have a 97 jetta gt it was running fine but then suddenly died going down the road and now it wont start. it backfires sumtimes when turning over. the timing belt is still on and im getting a buzzing sound from the fuel injectors like im suppose 2. i changed the plugs, wires. rotor button, and dist cap. i also got a used mass air flow sensor that looks like its n good shape at the junk yard and changed it out. while cranking the engine i held the coil pack wire up the metal and got spark but there is a couple cracks on the outside of the pack. im running out of $ and ideas please help!