MB 300E 1987 Problems
 

I have a 1987 300E. The car has a problem when accelerating from stop or low speed (while on 1st gear) it feels like it is trying to go to 2nd gear and 2 second after that you feel like someone pushed the car and it jumps forward a little changing to the second gear.
I know the car has engine oil leak problem and I have to refill every 500 miles.
What does the problem here? And what is the best Engine Oil for my model?

No first gear...
 

Your car starts on second gear. As far as jumping between gears, do a search, there are a couple way to adjust it. Steve Brotherton touched this topic before. It worked for me.
Good luck!

Yeah, you should adjust your BOWDEN cable. I believe you should loosen it a little bit. Do a SEARCH to find out more info.

Oil depends on your climate, if it gets real cold, use 0w30, or 10w 40 or 10w 50. But if you have climate like So CAL (never really gets below 40), then 10w 40 (or 50), or 20w 50 are good oils. If you are in the warmer climate, a thicker oil would be better... it might help reduce your oil leak.

GOOD LUCK!!