It's pretty tough to diagnose idling problems. Is this when you just start it, or does it do it all of the time?

The first thing I would check is to see that all of the spark plug wires are connected correctly to the spark plugs. Maybe one of them has fallen off. If not, you may need to pull the sparkplugs and take a look at those.

Sometimes a vacuum leak will cause rough idling, check to see if a vacuum hose has fallen off.

Sometimes contaminated fuel will cause a problem like this...Did this begin to occur after refueling? Let us know how long this has be happening and how many miles are on the car.

Hope this helps.

The Tenor Man

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Currently Driving.....
1987 Mercedes Benz 300D Turbo - Daily Driver.
2004 Buick Rendezvous...Smaller than it looks!
2005 Mitsubishi Galant - Not bad for a tin box...Lousey Seats
Past Vehicles.....
1994 Dodge B-250 Van- GAS HOG..Succumbed to rust!
1989 Mercedes Benz 260E - Totaled but no one injured.
1977 Mercedes Benz 240D - Loved it, but SLOWWW! - Succumbed to RUST!
1976 Mercedes Benz 240D - Same as above! -
1975 Mercedes Benz 240D - Same as above!