1993 Chevy S-10 Won't start

I a have 1993 chevrolet s10 4wd. The engine will not start unless I pour a little gas in the throttle body. Once the engine starts it may run 30 minutes or only a few minutes, then it dies, sometime it will start right back other times I have to prime it again. I checked the injectors with a noid light and it shows they are not getting a signal while cranking. A few weeks before this developed, on several occassions while driving normally the engine would start to run rough and the speedometer would act like a tachometer. This would last a minute or two then everything would return to normal. Any ideas?