BMW Repair: BMW 850ci has no power, bmw 850ci, gas consumption

Question
Hello, my 1993 850ci BMW has no power after check engine light on.  New tune up, but no Oxygen sensor changed.
Many $$ later mechanic thinks is computer or electrical?

Gives computer signalls for 15 - 20 things to include locked transmission thing...  Had 3 years ago wires in steering column repaired.

Check engine light on then off for awhile, good gas consumption and this mechanic did put higher fuse
in 9 mos ago for differnt problem?  

Any suggestions, it runs but no power...

Jim L


Answer
I would first get an accuarate account of the codes that are listed.Having the codes checked will be what you really need to know.What is happening is when your check engine light comes on the vehicle runs in a fail safe mode which probably your lack of power