Loss of power accompanies engine warming...but not when engine is cold!
 

Date: 9/7/2005
Subject: 190E Engine Missing & Stalling

Question
1990 Mercedes 190E 2.6. About 270000 miles.
After sitting all night, it starts without a problem, and runs fine for several miles or about 15-20 minutes. Then it starts to miss, buck, hiccup, fart and generally try to die. If it does stall, it takes a lot of cranking to get restarted. If I am on the highway, or if I can keep the RPM's at or above 1500 for 10 minutes or so, the problem resolves itself and the car runs fine for the rest of the day. This happens pretty consistently.

If it is anything like that I experienced in my 190e2.6, then it may be caused by a bad O2 sensor. Replacing that component completely fixed the problem.

I know that feeling all too well, of losing power when you need it. It can be dangerous, as it almost left me stranded in the middle of an intersection.

I hope this helps.