Ok. about a week ago i changed the fuel filter on my 92' 745T and after that the car has had driveablity problems to the point where i am totally out of ideas.

Basic problems include:
1) Hard starting 10-15 cranks (5-8 is normal before i changed the filter)

2) Dies on idle ocassionally after problems begin

3) Lack of power (hesitation) and diffculty driving above 20 mph or 1500 RPMs

4) Misfires at idle and when reving engine

5) After i can get the RPMs above 1500 (usually some pedal work involved)the car runs as if there wasn't a single thing wrong, (boost, accel, feel, sounds, everything) but once the RPMs drop below 1500 the problems recycle (misfire, dies, hesitation)

6) The car doesn't always drive off immediately with problems but about 5 miles down the road and the problem begin, and won't go away until i get the car home and try it again the next day. Then i go through the same routine again.

The things that i have already checked on the car is Fuel filter flow, kinks in the lines, fuel pumps, FPR, IAC, AMM, turbo hoses, fuses and relays. Since this is my first 740 i don't know where else to look.
Please for the love of God, Allah, Budha, and my brick please help.
John 1992 745T & 1994 854