You might try changing the OVP relay. Mine does that as well (420SEL - roughly the same engine, or at least the same ball park) and I was told by the dealer and my indy that it was the OVP. Just haven't had time or $ to order it and change it out yet

what is an OVP relay? mine also idles up whenever it feels like it. i figured IAC there.

Thanks Dave. I guess I will keep on looking- hopefully I will find a diesel. Thanks for the tips.

I actually want one because I like the styling, build quality and safety. Never thought about looking like anyone. If that was the case, I would have kept my Lexus LS400- (with the gold trim- which I hated). :D

Thanks for your input though- you have some valid points there.

I local 82' 300SD just showed up in the local paper for $1600 OBO. No details, except that it runs good. May check it out tomorrow. At least it is local.

86560sel

Buying a local car would be better because you can inspect and drive the car. A PPI is also recommended but make sure it's a thorough one. I had one done on my 300SE and the front end was shot but they must not have looked at it.

Not everyone on this forum is rude. Please keep us posted on your purchase progress.

wow, that sounds like a great car. let me know the results!!!

Goertz, the rough running when first starting sounds like your injectors. They're not too expensive, but you do have to multiply by 8. It is a common problem when the cars get into the higher mileage (125k+).

The rough idle could possibly be the OVP relay, but usually you'll have other systems malfunctioning like ABS. The ABS light is usually a symptom of a bad OVP. It seems many people blame the OVP for problems when that is not the case. Injectors could also cause a rough idle as could the idle control valve. Have you ever tried removing the idle control valve and cleaning it out well with carb cleaner?

Thanks
David

It sure does! I sure will!

no ABS light on. haven't tried cleaning the idle control yet. at will, it will idle up to almost 2000 at times for a few seconds, then drop down to normal. some times it does this repeatedly, sometimes not at all. it's been doing it more recently. the rough idle for a few seconds doesn't really bother me, but if it's a cheap fix, i'll do it. thanks for your input. i appreciate any help i can get.

The high idle is most likely your idle switch. I think the intake may have to be removed but I'm not sure. We had a similar problem with a 420SEL we had a year ago. One day, my brother washed it and it wouldn't start. Just kept cranking. Found out the coil was bad. After I replaced the coil, it would idle around 1500rps. It would not drop no matter what I did. So, I adjusted the linkage piece that goes to the air plate and that fixed it. The car performed just as it used to, which wasn't very well. I don't think I ever got that car running right. It pulled more at 1500rpms than at 3000rpms, which it did that as long as we had it (about 6 months).

I can't say positively that it's your idle switch since yours isn't a permanent high idle.

Thanks
David