My 84 500 SEL idles a bit too high, about 800 in D, but the problem is greater when shifting between D&R or R&D or into N it revs up to 1200 - 1500 and makes for a very jerky transition!

I have replaced the OVP (or OVR as some call it), the Idle control valve, O2 sensor, Injectors along with holders and boots, wires, plugs, distributor, rotor.

Thanks!