My 1986 300E has a fuel problem. I bought it recently with a fried fuel pump relay ( the connectors were melted ) and some nasty old gas in the tank.
I replaced the fuel pump and the relay after soldering a new connector plug for the relay. I also installed a new fuel filter and put fresh gas in the tank after draining out the old. The car ran fine for about two weeks then all of a sudden the car would stall out and not restart. i pulled a spark plug to check condition and spark, the plugs were black indicating a possible too rich fuel mixture ?, I changed out the plugs and the car started and idled fine for about 10 minutes then began to sputter and stall out. I tried to start the car again, it started and idled fine but when I went to give it some gas it cut out quick.
Any suggestions?