hey i have a 1990 750il with no acceleration, the rpms will only go up 1500. even if you floor the car the rpms will not pass 1500. if anybody has any idea, please let me know. thanx!

Your car runs in limpmode or emergency mode.
That can have several causes. The EML changes to limpmode when there are parameter which it cannot adjust between the 2 cylinder rows such as that the trottling valves are not synchrone running (max limit 2%) etc etc
Go to this side, there are the experts and you will get help for sure from us, as we concentrate on the E32.
http://www.bimmerboard.com/forums/e32/
Before that pls check and also mention that:
When ignition is in position 2, does the EML light blink for about 2-3 seconds in the dash or not?
What is the battery voltage without key in ignition, with key in position 2 and when engine is idling and at 1.500 RPM?
Do the stomp test. It is described on my website below. In case of the 12 cylinder you have to stomp 5 times for the one side, and 6 times for the other cylinder side.
What codes did you get?
Better indicate the VIN number of the car, so that we know exactly the engine type. There was a change if the engine from pre-facelift to facelift version, and they have different ECU's. The exact date = month and year of production you can find out from my website below under VIN decoder.