I have a 97 E420 and the engine rpm is surging at idle from about 500 to 1000 rpm up and down, in cold weather only. When the weather warms up a little it stops.Any ideas would be great. It starts happening at about 5 degrees.


Thanks

 

thy this you have whats called a purge on the left hand side of the engine compartment neer the washer fluid bottle its a little black valve there are two hoses running to it on is vacuum all the time one goes to your charcole canister. what i want you to do is when it is surging i want you to apply the parking break leave car in drive and disconnect the vacuum hose to this valve plug it with your finer does the surging go away if so replaced your purge valve (i call them a surge valve for this reason)

 

OK I will try that