Psfred and JimH,

I have the 87 300D 603 912 engine non turbo 138K Mi and the having the opposite problem very low cold idle speed that is still a little low when warm but runs fine otherwise. Also to note I have no tach on this model..

After doing search on threads it appears I may have electrical vs mechanical issue since several months ago this happened breifly then went away so I don't want to mess with IP settings just yet.

Since that time I replaced injectors, GP's filters ran cleaner through the system and did filters again.

So this AM removed two wire plug at back of IP cleaned the contact (tho not coroded) and reconnected. Started - ran slow - stalled actually restarted and then ran at a slow idle. Removed plug at back of IP - no change in idle speed. Seems to point to idle speed sensor on/near flywheel?

Since this is non turbo I cannot locate any idle speed controller/knob etc anywhere in engine compartment. Also what does OVP stand for and where is this relay located? Below/behind the fuse panel in the engine compartment?

All help and replies appreciated.

Carl