Hi All,

Looking for advice on a 2003 w211 E500 sedan. The car has had intermittent issues since I acquired it. The symptoms all occur simultaneously and include:

1. slipping clutch under low accelerator pressure on slight uphill inclines masquerading as light shudder, however it fluctuates in and out over seconds
2. transmission changes feeling rough and not holding on long enough
3. rough engine running (feels similar to a failed O2 sensor)
4. airmatic feeling too firm (esp in Comfort)

These all happen at the same time, and some days not at all. Other days it all works correctly and runs perfectly. The four symptoms never occur individually. In addition, I sometimes get suspension warnings, but also a random warning that my left rear number plate globe is out (it isn't). Symptoms tend to be worse after a long drive. Punching the throttle to force the revs higher fixes the issue, but only till the revs come down again.

Mechanic can't solve it, and has alternately suggested transmission control module, suspension system, and other things. Replacement of EGR valve did improve it (?) but didnt fix it.

I suspect a voltage problem. This week my battery went dead when left for 3 days. Same thing happened 12 months ago and battery was replaced, but symptoms above appeared both before and after. After drip charging it sits at 12.3v, 14.0/14.1 while idling, and while driving fluctuates from 13.9 to 14.2, though mostly 14.1.

My next thought was to swap out the voltage regulator.

Any thoughts welcome.