I have an 88 240DL. It likes to randomly shut off while I am driving. It runs perfectly fine other than that though. It's not just when it first starts or at a certain speed or around corners. It is completely random. Been trying to narrow it down by seeing if gas level or amount of time driven or even speed but it is completely random. If anyone has any ideas or knowledge to why it could be doing this it would be awesome because stalling out mid way through the turn lane is fun only so many times [:@]lol

 

I would start by checking the fuel pump relay and speed sensor.

 

I think the speed sensor (crank position sensor) is for 89+ 240s.

Three things to check. (1) The fuel pump relay, as Tech suggested. (2) The 25-amp fuse holder on the left inner fender. (3) The fuse panel at the left door jam. Clean them up, spin them, bend the tabs slightly for better contact, use a dab of dielectric grease (tune-up grease) on the contacts.