1992 190E surging while driving...Help!
 

My 1992 190E 2.6 just recently starting surging while driving. This seems to happen when the car is hot, not when its cold. It also happens when on the freeway or in town. Also, there appears to be loss of power when accelerating from a stop. I have already replaced the spark plugs and fuel filter. The plug wires are good.

Based on other cars I have had, I would guess the O2 sensor, but I really don't want to start throwing parts at a problem (especially when the O2 sensor for the Benz is $$$$)

Any one experience a similar problem and have a fix?

thanks

I would check the fuel pressure next! It sounds like one of the pumps could have failed.

If one of the pumps have failed, wouldn't the problem be there whether or not the engine is hot or cold? Problem seems to materialize when the engine has heated up, no surging when its cold, although when I do start the car it is a bit rough, requiring me to give it a bit of gas.