My 92 300E was running fine till Friday when I decided to clean the engine. I sprayed it down with Meguiar's All Purpose Cleaner, let it sit a few minutes and then rinsed it off. I left the hood up and let it sit overnight and when I went to start it the next morning it started missing on a couple of cylinders. I pulled the plug wires one at a time and it appears to be cylinders 4 and 5 that aren't firing. When I pulled the plug caps from the cylinders that were firing I could hear the spark arcing to ground, but on 4 and 5 I couldn't hear anything. I pulled the plugs and 4 was dry, 5 was a little wet, so I replaced #5 with a known good used plug. Still missing on both. I thought maybe some water might have gotten into the distributor cap when I rinsed off the engine so I pulled it off to have a look. It was completely dry and all the terminals look good with just a little bit of arcing deposits on them, but they all look the same. I ohm'd out the plug wires and they were all basicly the same, with just a slight variance possibly because of the different lengths. Can anyone think of anything else I could check? I've run out of ideas.

Thanks for any help.