Hi AlI, I know have seen a post about my question but I now I can't find. I have 96 sl 600 with 51K, recently after the car has become warm I will come to a stop and put into park and the idel will jump to 1500 rpm and bounce back and fourth to 2000 and back to the 1500 If I turn it off and restart it is gone. it onlyoccurs 1-5 times but if I rev the throttle at a warm idle it will do it everytime. Any suggestions?? Thanks in advance

 

I do not know if this will help but, my 99 S420 had a similar issue only that the rpm dropped at idle and would bounce upto 800 or so and back down to about 400. Turned out to be the fuel pressure regulator. For roughly $200 it was back on the road and have not had an issue since.

 

could be a malfunctioning 02 sensor - try unpluging the neg side of the battery overnight - that will reset the computer - if your radio has code protect, better have the code before doing this - pat