Hello, my name is Amanda.
I have a 1992 190E 2.3L W201 M102.
Recently it has been running with a high idle at roughly 2000rms, instead of the normal 700ish.

To combat this problem my bf and I have been shifting into neutral at red lights and revving the engine to lower the rms to a normal range (works 85% of the time).
Does anyone know what might be causing this? My bf tried tapping the micro-switch, and another part that little bristles brush over to see where the throttle is (something like that), but nothing has worked.

Anyways if that wasn't bad enough, my bf got frustrated with my baby, and while in neutral, revved the engine well into the redlining area. Later that day, we noticed the back light was very dim and one of the seat heater lights began flickering. Once home, the car was shut off, and when we restarted it the dash lights didn't come one at all. Now there seems to be a charging issue and the car is only running on the battery, however; we don't believe it has to do with the alternator. For the past 2 days we have been charging it over night with a trickle charger.
Any ideas of that's going on now?
We are planning on doing a diesel swap (see other post - Gas to Diesel Swap) in the next coming weeks so we don't want to put a lot of money into the engine.

Any suggestions would be greatly appreciated.
Thank you very much for your time.
Sincerely,
-Amanda