93 960 No start but starts when 1 plug is removed STRANGE!

[badgator]

I bought a 93 960 148K dirt cheap yesterday. Last owner replaced fuel pump (didn't ask if fr or rear) after he ran out of gas and wouldn't start. Wouldn't start since, I pulled code 123 - rear ect was unplugged. Valve timing correct. Tried WOT cranking for a few minutes (30 sec max at once)to no effect. It's on the verge of running but just won't start. Fuel pressure seems good(don't have guage). Tried resoldered fuel relays no effect. I checked for spark, seems somewhat erratic to me. THEN IT STARTED AND RAN WITHOUT 1 SPARK PLUG in # 2 or 3 or 4 (I was checking for spark with a old plug, removed 1 from engine and tried, don't ask me why I did this I don't know, didn't check all didn't seem necessary) although compression was blasting out. What the hell why won't it start with all plugs in (recently replaced bosch platinums). The flame trap was cloggd replaced it. Changed cam sensor no effect. Added plenty of gas to tank, tried dousing card cleaner into TB no effect. No other codes, wiring seems intact. Will a 850 crank sensor fit? I tried to remove the 960 sensor is it a T25 bit? It isn't a 10mm like my 850. Any comments / suggestions?