Just got off the phone with Rob, and the dealer thinks they've found the problem. They let the car idle for a while this morning, and sure enough it started running rough.
Still no codes.
Rob went by not too long ago. They had taken an ignition module of some kind out, and replaced it. The tech replaced the plugs while he was at it, and checked the plug wires and other ignition parts.
When he was there, it was running like a top. The service manager is going to drive it over the weekend, to make sure they've nailed it.
They can't explain the "no codes" condition, but seem to be working hard to fix it regardless. This morning, quite quickly, they determined it was bad "spark" and not a fuel delivery problem. Then he started at the plugs and worked his way back...
I'm just sorry that the tech will be paid "warranty" rate for this fix. Looks like he found the problem quickly and without much fuss. Didn't need a "code."
Rob's owns a gourment foods manufacturing company, and is going to drop of some goodies next week. I think the dealer made a new customer...
1998 C230 "Black Betty"