First of all I would like to say that this is such a great site that I have been able to fix a lot of my cars problems by just using the search function and looking for similar problems that the other problems have had. However, there is this problem which I still can't seem to fix. My car by the way is a 1987 260E and I am from the Philippines where there is no reputable shop that can fix Mercedes cars so I have to do most of the job myself. The problem is when my engine warms up to operating temp (80-90) the idle would just swing wildly from 500 to 1100 rpm. It doesnt stall the engine though. This condition is agravated when the airconditioner is turned on. I also cannot get the car to idle below 1000 rpm when the airconditioner is turned on. It would immediately swing wildly so I set the the idle to 1300rpm without the aircon and when I turn it on, it drops to 1100rpm. However at these idle speeds, it is very difficult to change gears from nuetral to drive or reverse as the car would lunge forward or backward because of the high idle. Based on the search on this site, I have already done the following:

1. changed spark plugs
2. changed high tension wires
3. changed OVP
4. changed idle control valve
5. checked for leaks
6. changed idle actuator
7. checked all fuses
8. checked wiring harness

Still the idling problem persists. What do I do next. Any help especially from the benz experts would be highly appreciated.

Nikos124