Rough idle, no start w/o gas pedal on 93 300E 2.8 with 107k leads me to buy a new OVP. Helps the warm starts, but still idles rough. The car sits in my garage for 30 days while I try to sell it. The wife wants a wagon. After a 30 days hiatus, I start it up to take it to a potential buyer, and it won't restart for the buyer after it's warm. Starts for me, but now the buyer's spooked and he walks. Okay, time for a real tech to take a look.

My all-MBZ tech and his indie shop tell me that I first need a new wiring harness - he's surprised the car runs as well as it does, with so many shorts, he says. He can't even diagnose anything else until it's in. Okay, $513 harness plus diagnose and installation (plus a new driver's door stop, to bring the "crack - crack" back to a satisfying and subtle "thunk - thunk" as the door swings open) brings me up to $680. I'm cringing, but not yet in pain.

Now, the zoinker. I call him this a.m. and he tells me the car now starts fine, but still idles a little rough, and from time to time, can stall under the right conditions. The car's driveable, but he recommends an "Idle Control Box," his exact words. He says it costs $700 new, that no units are 'reconditioned,' but that installation will be a snap (so THAT part won't cost much). I'll be lucky to get out of the door under $1500 when it's all over.

NOW I am in pain.

1.) Do those puppies actually cost $700? And there are no reconditioned units available?

2.) Should I just try to sell as-is, with a slightly rough idle, for $12k firm, or should I suck it up, put the new idle unit in, and sell for $12.7k? (or should I get a new valuation tool?)

Any advice would be much appreciated.