i have a 99 grand prix gtp i was out driving stop for about an 1hr came back started it up made it about 3 blocks and it died i got it started again but it was running real rough i could hardly keep it running and the exhaust smelled i thought it was the converter plugged up thats what it acted like and with the smell i thought that was what it was but it was wasnt does anyone have an idea what it could be