Engine Performance problem
1986 Mercedes Benz 190d 4 cyl Two Wheel Drive Automatic 200000 miles
I have a Mercedes 190D 2.5 - 5 cylinder. Just got it a few months age. The engine had new rings installed before winter. The car ran very strong and started well in the cold (4 degrees). The car had good power but ran a little rough. Well as I have been driving the car it seems to have times that the car slows down feeling like a miss than picks up and rides great. Recently the car has been getting worst and now is blowing some black smoke. Its becoming very slow on some hills where I had maintain 60mph now slows down to 40mph. When they put rings in this car they did nothing with the top half I kind of felt it needed the valves adjusted because it idle rough and noises. I did do a quick check on the injectors by loosing the fuel line. The engine changed each time. If the valves needed ajustment would it run this bad. Also I was surprise to se just a little squirt of oil when I loosen the fuel line I thought it would be a hard spray.