Try putting a bottle of redline fuel additive and see if that helps. If that does not help, you should consider replacing your pooped up injectors.

Thanks for the suggestion. I just got some techron and put it in with some new gas. It didn't act up for the whole trip and you can barely feel it running. Fingers crossed.

So I went on my trip... Voltage regulator failed. The brushes were worn out. Good news is that it hasn't hesitated since I changed the regulator. Bad news is that it is consuming some coolant. ahh well.

Update: The car started mixing fluids so I changed the head gasket. The bolts on the exhaust side of the head were all relatively loose and there a build up of carbon on the exhaust side of all of the cylinders indicating compression leak. As far as I could tell the head gasket had been changed improperly. So far I haven't had any problems and the car no longer hesitates. It still does the start-die-start thing sometimes, but I think that is a separate issue.

Start and die problems can be the
(a) Fuel Pump Relay
(b) Crank position sensor.

You can measure the resistance of the CPS at the EZL should be between 820 - 1,00 ohms.
Fuel pump relays are famous for having dry joints on the circuit boards.

cold start
 

Had the same problem twice with my 190e. First time changing the OVP helped. Second time I changed OVP and rotor with no success. Finally took it to a shop and it was the ignition coil. Had no problem since.