At a loss

[Michael Bowman]

Ok Guys, 

Got a 94 G20 4.3 vin Z tbi.

Been working on this for days. Got van cheap. It ran but had bad skip and misfire. Ok. Replaced plugs, wires, button and cap,  oil and fuel and air filter. Still has skip and rough idle. So replaced IAC, TPS, rebuilt pressure regulator and replaced injectors, new fuel pump and engine coolent sensor. Removed brown wire with black teacher, set TDC, and at 0* . Still no start,  plugs drowning in gas. Injectors cut off when I open throttle fully. It's got spark down to all 6 plugs. Maybe not enough, how can you know what's enough spark, was thinking either bad pick up or ICM, but like i said got spark and injectors fore until throttle is fully open. Any help I can get would be appreciated. 

Oh yeah had it about right and next day and until now. Cranks over but nonstart. 

[Duelin]

Have you done a compression test?  A lot of the engines from this era had soft cams and the lobes would wear down.

[Michael Bowman]

Yea have done compression test , all cylinders reading 130 or more. I think it's a timing issue. Going to dug into it again today. Will let you know what I find.