Not sure how to describe this problem but while I am drivingdown the roadthe carjust skips,burps, or hiccups. Not a backfire but a hiccup its the weidest thing. While I am driving down the road it could be 30mph or 60mph andthe RPM needle drops for a milisecond and just keeps on going. It does not do it all the time but when it starts its bad for a while ( 10-20 minutes ) thenstops. Its usually after it has been driven forseveral miles. Any ideas.