Why does my 1999 GTP engine keep sputtering?
Why does my 1999 GTP engine keep sputtering? My 1999 GTP experienced the sputtering problem at 28,000 miles and it was the result of a defective wiring harness. I assume this to be very unusual but it can be the cause. Best of luck. 30 people found this helpful. Why does my Pontiac Grand Prix not start? 26 people found this helpful. When your car starts fine cold, then fails to restart while warm, it is usually a coolant system problem. Either low coolant, or bad coolant level sensor. 26 people found this helpful. What causes Trac off on a...