Mercedes-Benz 240

2004 Mercedes-Benz 240 Engine   

At highway speeds a puff of white smoke?? comes out the exhaust occassionally (every 15-20 minutes)and last only 2-3 seconds. The check engine light is on and reveals misfire on 1 cylinder. When I slow down the car idles very rough. If I cut engine and restart it idles fine. No smell of oil smoke. The car has 58,000 - original plug/wires. Thanks

Hello,

Any warranty left?

Are you losing any coolant?

You may need to inspect the coil for signs of cracking or corrosion. Also remove and inspect the spark plugs for the cylinder. The condition of the plugs is often revealing. Give me an update.

The only warranty left would be the 8 yr/80000 mile emissions. Radiater less than a cup low. Have not checked plugs yet

Is the smoke clearly white?

Yes puffs out clearly white plume less than two seconds. Does not do around town - lsdt night check engine light went out. All I did was check coolant

Inspect the spark plug to see what is going on in that cylinder.

spark plug fouled - changed plugs and wires. Still smoking about 5 seconds on start up

What color was the plug? Was it carbon fouling, black sooty deposits?

If you are still getting the white smoke you will need to perform a leak test on the coolant system to determine where the leak is.