My 85 380se has 204k. I've only had it for a couple of weeks. Just replaced plugs, wires and all that stuff. I just checked my mileage and was pleasantly surprised! 202 miles on 10.3 gals. That works out to 19.6 mpg! That's combination city and highway driving. 70-85 on the highway trying to work the bugs out. This car has been sitting for two years and has an idle control problem. Hopefully with the idle fixed and a new fuel filter it'll get even better. I love these cars!! Have you had a tune-up lately? Also check for dragging brake, I had one binding on the right rear
That'll suck up some gas!! Good luck.