Its only running on like 4 or 5 cylinders, we've already checked all of the obvious, it happened all the sudden and compresion is fine, any clues?

fuel or spark?
Check rotor/ cap for arching isolate dropping cylinders.

I had a problem with the shift interupt micro switch causing to shut down cylinders

EFI/MPI? Not much info to work with. A failure of one of the injector driver circuits will suddenly take out 4 cylinders. Just a WAG.

Dave

MPI, could both of you guys elaborate, because I did have a broken injector and a nuetrel saftey switch go bad, which is wired around right now

only 92 hours also, we just had a head rework from a valve seat issue and now this?????? 6 weeks down and counting, there goes the summer

Need more info!

What year? VST or Cool Fuel?

Did the problem start immediately after reassembly from head work? Or did it run fine for a few hours, then developed a new problem?

Did you check for trouble codes?

What does "checked the obvious stuff" mean?

Have you checked fuel pressure?

Which cylinders are missing?

Dave

2000
cool fuel
It all happened at the same time, dropped a valve seat
plugs, wires cap, rotor all checked
fuel pressure 42-43
Im not sure which cylinders, but can find out tomorow

I just got back from the shop and he said the shift micro shuts down 4 cylders to shift into gear and if I wired around the nuetrel saftey switch it is probably stuck in that mode, what do you think, we are trying to fix that now

is it a Merc or Omc if Merc alpha or bravo?????? if alpha it has a shift interruptor if bravo it does not. only Omc shuts indv. cyclinders Merc grounds the coil for a milisecond.

It is a Bravo, what does grounding the coil do