So my dad just bought my 1995 E320 wagon off of me which was running great. The motor needed cleaned up so he decided to hose it off (not power wash but still hose!). Now it runs like crap like its running on four cylinders. I had him take the valve cover center piece off and check the plug wires and coil packs but he said it was dry as a bone under there. It is an HFM motor which I am not familiar with. I guess there's no distributor but it sure sounds like the problem you would have with water under a distributor cap on an older car. Any ideas and or pics/ diagrams would be helpful! Thank you in advance!!!