::::1994 C220 idle problem after start-up:::::
 

I start the car up and when I press on the brake the idle dips real low and is pretty rough at times (occasionally it dies). This happens every time I start it up and press the brake to put it in gear, so what is the problem? I've read that it may be the air flow sensor, can anyone give me some insight?

Possible leaking Brake Booster

Ok, new info. It's always right after start-up and it doesn't matter if I put on the brake or not. The idle problem goes away after a couple minutes and today the idle dipped down real low and was sputtering.

Yes, looks like a vaccum leak in the brake booster. Remove and plug the vaccum line going to the brake booster and see if the idle becomes regular again.

This is good advice. It's simple, quick, and best of all, doesn't cost anything. Give it a try.

IMHO however, I think the problem is the throttle actuator. With age, the actuator motor gets tired, and has a hard time overcoming the resistance of the throttle return spring.