Car won't idle smoothly cold....goes up and down from 1500rpm down to 500 or even stall out....give it a little gas and keep rpms up it will run smooth. Once hot, idles OK..Also when this started, the radio started acting up...it will come on and go off...sometimes the antenna would not extend or retract with radio power button. Window switches would have to be held down to lower....the "resistance point" on the rocker seems to be bypassed...and the windows seem to run faster than before. Instrument panel lights come up brighter...battery seems to be draining during inop time...headlights and wipers seem to be brighter and run faster than at idle...

Is there a relay or something where all these functions run through that I should be checking? This stuff all started at the same time....so I am sure I have a short or ?

Thanks in advance.....

 

on the charging system.You may have a battery going on you or the alternator or a high voltage condition from the voltage regulator.
Just one place to start.

 

I had the exact same problem on my 1990 E300. The voltage regulator was worn down to the point that it wasn't functioning properly anymore. Have your trusty indie mechanic pull the voltage regulator and check it out. Spend less than $200 instead of God knows how much for a full alternator. Best of luck to you.

 

ur overload protection relay is going crazy

 

It's has a mis-fire... check your sparkplug wires also wiring harness...