Indeed, it can be bad EFI trigger points, or a bad ground for the injector wiring. Check the mass of cables connected to the body/frame behind the battery - that's where the fuel injectors are grounded at. Make sure it's clean and rust-free. To check each individual injector, get a long handled screwdriver and hold the tip of it against the base of the injector, and listen through the handle. You should hear the sound of it firing (several times per second). If you don't hear each one, you've isolated your problem. Remember, injector sequence is:

1 + 5
4 + 8
6 + 3
7 + 2

If any of these "pairs" aren't firing, then you probably have dirty or bad EFI trigger points. I bet you have grease or something else crudding the points up - they're located inside the distributor and you need to remove the dizzy to access them. I highly suggest you do this and give them a good cleaning with PAPER or a soft CLOTH (NOT SANDPAPER EVER!). Make sure there's no lint on them on reassembly. And by the way, snip the wire going to the condenser. It causes more troubles than it's worth.

Munich: M117 V8's are EFI and don't have a heat riser plate