Help-Idle Adjustment-1990-300SEL
 

Where is the idle adjustment on the 1990-300SEL Engine... thanks for any info... Jim

There is no "idle specific" adjustment on your '90 300-SEL.

Post your problem and perhaps it will get solved.

Yes, that is correct the idle is controlled electronically.

Idle Control
 

The car idles at 500 rpm but the power steering shakes the steering wheel... At 700 rpm the steering is fine... Any Ideas electronically???? Jim

500 rpm idle sounds a bit low. Idle speed shoud be 600 or so and is maintained by the ECU and not adjustable. The idle air valve regulates the idle based on input from the ECU. The idle air valve might not be doing it's job and need cleaning or replacing. The rubber hoses on the valve are prone to leaking too.

Another thing to note: the shaking you describe could be caused by a bad engine mount. I have had two fail and they caused the shaking you describe.