unplugged injector plug no diff

[tnporsche]

1988 944 rough idle I unplug the injectors one at a time. # 1 and # 4 make no difference in the running.

I have swapped # 1 with # 2 , and the problem stays on # 1 and 4 , so that means the inj is ok.

I read somewhere that the inj are batch fired 1,4 and 2,3



I also hooked a scope to the inj plug
(I sckeched this close to what I saw, I think I can download them)
The first one is the patern in the memory
The second is mine on #4 (I can't check and compare to two or three, it goes dead)




What can cause this?

Can it have anything to do with ref sensors? (or is it a start on no start with it?)

Please help