I installed a new fuel filter, and the car is running much better. However the idle is slightly rough and the engine still surges badly during full throttle. I appreciate any help you can give me. It is a 1991 190E with 2.6 Gas engine. We recently got the car on the road. I had been sitting for several years. Our mechanic replaced the fuel distributor, fuel injectors, and cleaned the gas tank. When I replaced the fuel filter today, the fuel pumps did not look like they were new. I may have misunderstood our mechanic.