I've had my '90 560 SEL for about 500 miles and recently after sitting through a couple of drive-thru's (bank & fast food) it hesitated really bad when starting from a complete stop. It felt like it was going to stall out, but didn't, the fuel just seemed to cut in and out but the tach never dropped below idle. The coolant temp was probably around 90/95 (c) at the time and the outside temp was around 72 (f). Once I got going there was no problem with throttle response. At the next stoplight the car once again exhibited the hesitation, with the fuel seemingly cutting in and out. I'm running premium fuel, it wasn't a really hot day (by West Texas standards), but the car does have 202K miles on the motor. Anyone have any ideas? The car also seems to run on the rich side, especially when cold.

TIA,

MJ Miller