1995 E320 misfire

[colincoon]

Hey guys, desperately need your help.

A buddy of mine picked up a 1995 E320 wagon this weekend and it was running fine during the test drive but two days later it wasn't. It would choke up and die after a while and after sitting for a bit would fire up just fine. Turned out to be a bad fuel pump, we could hear it ceasing up while it was running.

Replaced the pump with a good used one and took it for a ride. It worked GREAT for about a mile, then it started to cough. Once we got it home it was misfiring pretty badly. We thought that maybe the pump was already bad, but upon bench testing it was fine. We decided to replace the second pump just to be safe and it still ran terribly.

BOTH pumps are working fine.

After spending a few hours trying different things we determined that cylinders 3 and 4 are not firing. We replaced plugs with the correct Bosch ones, and replaced coil packs with new ones. Upon doing this we noticed that there was oil on the plugs and replaced the valve cover gasket. It was leaking pretty badly.

I tested it by unplugging one plug at a time and noting the difference. I then checked spark at each plug, and ALL SIX have spark. Next I unplugged one coil pack at a time, and only the 3 and 4 pack had no change. I checked the injectors to see if one wasn't getting power, and all six have 13+ volts.

The car will start, run and idle but it is missing pretty badly.

The wiring harness and throttle body are new. The OVP is new, and the fuel pump relay is new.

Anyone have this happen to them? We are taking a break now but are really out of ideas on what to do.