Tech help please, 600sel, flooding
 

Sorry gentlemen, tried to edit my post and lost it.
1993 600sel. aprox 120k miles on clock. I was enroute across the province this morning with the cruise set at approx 120 kmh, the car lurched/surged, then settled down for a few minutes. Surged again, the fuel consumption meter pegged wide open. The fuel consumption is astronomical, no warning lights, oil pressure is fine, not overheating, or running any warmer. There is smoke on acceleration. I stopped at a service area, added gasline antifreeze, topped up the fuel. Car will start and idle with no problem, will run down the road, although the engine feels like it is bogging under light acceleration, will accelerate normally under WOT conditions. Fuel filters were changed at Xmas, plugs/air filters about 6 months ago. Acceleration produces blue/black smoke with a distinct rich mixture smell. I am at some distance from the house, and could use any suggestions/directions as to what to do..... Car had been running perfectly to this point (2 hours into trip). Any suggestions/direction to proceed would be greatly appreciated. Many Thanx.

Local dealer is telling me that the OVP could be gone...I wasn't aware that the 600's had an OVP....if so where would it be located. Thanx