That's a good point. I will check those brushes. Great starting point (and possibly finishing point). EDIT: I just checked the voltage at the battery with engine on and I get around 14.3 to 14.5V regardless of RPMs. The original owner said it doesn't act up for a while though so maybe eventually it rises. I'll have to monitor this next time there's a throttle issue. The car had bad tires for what that's worth.

I just read for codes and got the following:
PIN 8 Trouble Codes:
9 O2S 1 (before TWC) - voltage too high, circuit open or voltage implausible
11 O2S 1 heater (before TWC) - Current too high/low or short circuit.
42 CAN communication from ASR, EA/CC/ISC module or diagnostic module (OBD II) faulty
46 Resonance intake manifold switchover valve - open/short to ground or B+

Pin 14 Trouble Codes:
2 EA/CC/ISC control module (N4/1) or Safety contact switch (M16/1s1) or Stop lamp
switch or Cruise control switch or Actual value potentiometer or Starter lock-out/back-up
lamp switch or engine speed signal or vehicle speed signal or closed throttle position
switch or safety relay in EA/CC/ISC control module
11 Closed throttle recognition signal to engine control module (HFM-SFI or Left LH-SFI)

__________________
-E300d '99 350k
-Suburban '93 220k
-TDI Jetta '03 350k
Sold
-F250 '96 7.3
-Dodge Ram 12V
-E320 '95 200k
-E320 Wagon 1994 155k
-300d Turbo '87 187k miles
-E320 1994 200k
-300d Turbo '84 245k (sold to Dan62)
-300d Turbo '84 180k
-300sd '80 300k
-7.3 Powerstroke Diesel 15P Van 500k+ miles
-190d '89 Non Turbo 2.5 5cyl 240k (my first MB)
Tom's Imports of Columbia MO Ruined the IP in changing leaky delivery valve O-Rings - Refused to stand behind his work. Mid-MO MB drivers-AVOID Tom's.