This is my second thread today. Purchased 300E recently that has some history. Would like some feedback to get car running smoother than it already is.

The car is a 1989 300E that has been sitting idle for little more than a year. The original engine (202K) was replaced due to head gasket leaks. Found same car with only (52K) on the engine. Engine was swapped however the mechanic was not very knowledgable in MB's.

First things done were two new fuel pumps and fuel regulator installed. New battery of course, thermostat. After these intial things car idles rough while in park (just under 10 RPM) but just above 5 RPM while in gear. Drives pretty good though. Since the first wave of repairs had new radiatior and hoses, and bushings put on.

Main concerns: during accleration from stop, the car sputters; there is an annoying rattling coming from under the car on the drivers side; gas gauge flutters (gotten better lately with a few fill-ups); sunroof does not work at all.

Any direction given on trying to resolve any of the above issues would be greatly appreciated.