I have a 1990 560 SEL with the most unusual problem.
Once the car as been parked for several hours or overnight the car will start, idle and run perfectly.
Here is the problem
1. Start the car and operate it for 10-15 miles to get to operating temperature.
2.Stop and kill the engine for 45-60 minutes- not 20 or 30 minutes or 75 minutes or longer but about an hour.
3.Start the car after 45-60 minutes and it starts great but once you put it into gear it will begin to hiccup and the engine will sputter and almost die.
4.Put your foot on the brake and take your foot of the accelerator for a few seconds then reapply gas and the car will accelerate fine and run great until you stop for another period about 45-60 minutes.
Car has been in shop 8 times for this problem and had numerous adjustments, resealing of vacuum system, new spark plugs and wire, new coil and wire, two new fuel injectors, replacement of one of fuel pumps, and replacement of idle module.
Anyone have any suggestions?

Not sure if this has been replaced. I don't remember it being on the list of items replaced and I will call tomorrow and ask the mechanic that is trying to find the problem.