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Old 07-17-2002, 01:43 PM
suginami suginami is offline
Join Date: Dec 2001
Location: Southern California, U.S.A.
Posts: 8,503
I've been reading the posts and noticed the following:

1. You have the same 3.2 liter M104 engine as in Haasman's 95 E320, which is also very similar to the 2.8 liter version in Dave C Klasse's 95 C280.

2. Memphis10c has a diesel model, so there are surely no similarities with his problem and yours.

3. drbrandini has the 3.0 liter M103 engine in his car, and these engines are very different, have different fuel injection systems, etc. Your idle is controlled electronically, his is mainly mechanical with electrical help (from what I understand from Stevebfl's posts).

Do a search on M104 hestitation and see what comes up.

I know from experience with my car and reading many posts here, the obvious things to check with this problem and M104 engines are:
1. the engine wiring harness. They were bad from 93-95, and if yours hasn't been replaced, do it now.
2. spark plug wire resistor ends. On M104 engines, these are very frequent causes of idle problems, missing, and hesitation under load. The spark plug wires on these engines very very rarely go bad. It is always the end or boot of the wires. These engines use 3 coil wires and 3 spark plug wires. Each coil is responsible for two cylinders. It is usually a bad connection of the boot on a coil wire that causes the miss. If it's not your engine wiring harness, my bet is that it's this.
4. Mass airflow sensors can cause idle fluctuation problems, but my guess is it is not your problem.
5. Throttle actuators can cause this problem. The wire harnesses also go bad on these units. Stevebfl has also said the throttle actuators have potentiometers in them that also go bad or wear out. Usual signs that these are going out is your cruise control starts to go out, your idle will fluctuate up and down rapidly at idle, or under acceleration your pedal will be very sluggish. My best (uneducated) guess is that it's not your throttle actuator.
6. Your problem could also be fuel supply or fuel pressure related. Check your fuel pressure relief valve, fuel accumulator, fuel filters. You also have two fuel pumps, but they rarely go out.

Just my .02 cents. Hope it helps. The best thing about my advise is that it's free! No charge to the reader.
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Last edited by suginami; 07-17-2002 at 02:38 PM.
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