intermittent stalling

can anyone advise?
engine cuts out suddenly :frown: - usually the second I drive over a bump on the road. otherwise runs fine, no misfires or anything.
when it cuts out, lights, heater etc stay working. RPM's fall gradually in line with speed as I coast to a stop. it will only 'bump start' if the key is 1st turned to 'off' then back to 'on' or it will restart immediately with the key as long as its switched off 1st. no difference if hot or cold, but most frequent when driving 50mph plus.
Replaced DI cassette, crank sensor, fuel filter & relay before realising it was bumps in the road causing the problem.
I think its got to be a bad connection somewhere but don't know which one(s) could cause just the engine to cut whilst not affecting anything else.

look for damaged ignition wires ir a bad connector to the directignition unit if so applyed best i can do from here

Had a simmilar problem, it turned out to be the fuel pree-pump. For me it would be worse in hot weather and / or if the tank was low. Othewise might be the primary pump on the way out to, if you have over 200'000 kilometers I'd be suspicios of the pree-pump.

How about the ignition switch, there are wear points on these cars! If you fiddle with the key in the ignition does it do it?

i have seen ignition switches cause similar symptoms. might be worth it to check fuel pressure too.