Question

hello, i hope you can help, i own 89 bmw 32 735il, im trveling t 100km/h and all of a sudden car loses speed. the tacho stays at 2000 revs, but car loses speed, feels like it runs out of fuel but then it kicks in suddenly and with kick s revs are still p there on 2000.
it has a new fuel pumps 3mths old, the fuel filters are clean and new.
i suspect that it may be gear box, but noew a new simptom, the revs completly cut out then udenly the car was off again running t normal speed.
coul the coil also be at fault? any advise wouls be much appreciated.
mechanic could not finf falt as it was not apparent when hooked up to o clled diagotic computer.
he suggested i take it to shop were they have performce car dyno meter, were i can run all four wells and have the car running on the spot while connecte to machine, please help. eric, melburne, australia