Guys,

Thought I'd follow up with an update for those who were wondering how this turned out.

Dropped it off at my usual MB mechanic and he figured out that it was the Air Flow Meter (the large unit under the fuel distributor). This unit has a large plate that is moved by the air. On the side of the unit is a "rotary" type potentiometer. Resistance is varied based on how much air is moving (and therefore pushing on the plate).

Mine was apparently flaky. When the throttle was pushed lightly, the unit showed no resistance whatsoever (open circuit). It was causing the computer to "guess" how much fuel to use.

An apparent secondary problem was the O2 sensor. My tech says this type of problem can certainly kill an O2 sensor but it could have been something else also (ie. age, running rich in the past, etc.)

Since it's been changed, I've started it cold once and hot 3 times. I *never* needed to push on the gas pedal while starting (much less pushing it to the floor as I did before!) even when starting hot. The hot starts catch immediately (< 0.5 seconds) and the car doesn't stumble and runs perfectly. I'd say there is approximately 10% more engine power in the low end (if not more) than before.

Apparently this part is $1300 new and I was lucky that he found me a used one for $300.

Neal

__________________
'83 300SD 335,000km (207k) mi SOLD
'87 560SL 163,000km (101k mi) SOLD
'86 300SDL 356,000km (220k mi) SOLD
'92 500SEL 250,000km (155k mi) SOLD
'90 300SL 140,000km (87k mi) SOLD
'01 S430 260,000km (161k mi) SOLD
'03 SL500 167,000km (104k mi) SOLD
'07 S550 4MATIC 235,000km (146k mi) SOLD
'07 GL320 CDI 4MATIC 348,000km (215k mi)
'13 GL350 BlueTec 4MATIC 170,000km (105k mi)
'14 SL550 72,000km (43k mi)