Rough Idle After Stop -HELP!

I am at my wit's end with this problem. I have a 1992 400SE with almost 89,000 miles.
The problem:
It cranks fine. When I come to a stop that last more than about 30 seconds, the car begins to idle so roughly that the car is shaking. If I try to accelerate, the engine continues to run roughly and the shaking continues. There is a definite loss of power and the car is struggling to run. The only way I can correct the problem is to turn the engine off, immediately restart and it runs fine. The problem might begin again with my next stop, or may not.
What is frustrating is that this problems is intermittent, but is getting worse. My shop has observed the problem.
The first thing done to try to correct the problem was the additon of a fuel cleaner to the gas tank. Did not work.
I just got the car back from the shop 2 days ago, after a one week stay 60 miles from home. The Wiring Harness was replaced under warranty by MB, thank goodness. Also, a new Crank Sensor was installed and positioned. My bill notes "Run DTC found code for crank sensor, replace sensor". The senor was $171.32 and "positioning" cost was $163.80
The car ran fine for 2 days and today the problem returned.
The idle problem is not related to how long the car has been running. The problem might occur 5 minutes after the car has been running, or one hour. Wet or dry, hot or cold conditions do not seem to matter.
Please help! This is driving me crazy.
Thank you!
North
p.s. I am female, so please reply in "non-tech" language.

The wiring harness and crank sensor were the best place to start. The harnesses do not handle the heat in the engine compartment as well as they should. I am confident that it was needed.
Your running problem does not sound like the ignition system. It is very common for the contacts in the distributor cap to turn green with corrosion. But turning the engine off and back on would not 'cure' this.
Another common problem with your engine is the throttle actuator. This is also called the throttle plate and it opens and closes as you depress the gas pedal. The electronics and even the wires inside of this unit are also vulnerable to the high engine temperature. I have seen them taken apart after replacement and the insulation has become very brittle and breaks off. If this unit is still the original one, that could be your problem.

Good luck.

My first inclination is to "address" the $330 charge with your mechanic if that was to be a fix for this problem...

Thank you both!!
I have very blonde hair, so please forgive this question. What should I say to the mechanic/dealer about the $330 charge? Should I refuse to pay it? I am frustrated that the "repair" did not fix the problem. If you were me, what would you do about the repair costs? Thank you all your help!

[engatwork]

Just tell them that the problem is still with you and see what they say - if they balk or seem to be reluctant to help you out without charging more $ then start up about the no payment thing. If it a reputable shop they should try to help you resolve your problem without resorting to this avenue of resolution. The next thing would be to find another tech/shop.
Jim
'85 300D
'95 E320
'97 CRV

[JimF]

North,

[In my reply, I'm *PURPOSELY* going to be a little technical because YOU must be able to *communicate* with the shop personnel.]

In my S500 cpe, I had a *similar* problem in that the same Diagnostic Trouble Code (called 'DTC') would appear. This DTC code 17 says that the CKP (CranKshaft Position) sensor was bad. Same as yours. But if it's bad, the car won't start or run!!!

After lot of investigation, the *REAL* culprit was the Ignition Control Module (ICM)(N1/3). That's where the CKP sensor plugs into. It's located on the driver's side on top of the left fender well, under the protective cover.

To see what it looks like, click here: http://pages.prodigy.net/jforgione/MB_DI.html The CKP sensor plugs into '2' position on the drawing.

Ask the tech to 'swap' of the ICM module for a trial. And of course, you want $330 applied to *really* fix the problem!