1990 740 B230k hesitating and cutting out

Can anyone lead me in the right direction please. I'm working on a friends 740 which has the lovely 230k engine in it(Not) and its auto It will start fine, idles lovely, drive down the road half a mile and it starts to hold back then it starts to lurch until it eventually dies. It will start back up straight away and then run for half mile again before holding back and cutting out again. If you knock it into neutral then sometimes you can rev the engine to clear it but normally it needs tyurning off and starting again. I have checked dist cap, rotor, plugs, hall sensor, i have changed ignition amp(module) i have checked engine earths fuse etc but can't find anything Any ideas anyone

IIRC the B230K in the 740 uses a Pierburg carburettor - if this is what you have there is an issue with a plastic clip holding the choke actuator, so you could check that.

All sorted now the float levels where wrong in the carb, and the second chamber was partially blocked. Cleaned out and reset float levels and the car runs great.