89 420SEL hard starting

[Dave Henderson]

This newly acquired car doesn't like to start up! It has to be cranked over and over and trys to catch but it takes lots of trys before it will even idle roughly. then it won't rev up for a while. After it does it seems ok and re starts easily. If I give it a shot of starting ether when it's cold it will catch, but still must warm up before it will rev up. Seems obvious that it needs a richer mixture when cold. I'm an old wrench turner but inexperienced on fuel injection. i'm getting the "Check engine" light too, (related?) maybe because of a bad plug wire at the plug cover. Thought I'd slip off the distributor cover and substitute another wire, but the 3 screws on it are very very tight, don't want to wring them off. Frustrated! Any help much appreciated. Dave