I've dealt with the same symptoms on my 85 380SE, I replaced the accumulator, injectors, OVP relay, coil, plugs, rotor & cap. It was still revving high (1200-1500) when warm. The accumulator solved the hard starting when warm or after sitting for a week. The rpm issue was never solved until my fuel pump relay gave up. A new one solved it but just this week it started to do it again. I need to go through all the ground points and confirm they're clean and tight.

__________________
Democracy dies in darkness, you have to kick at the darkness till it bleeds daylight