Having troulbe cold start up. From top to bottom here it goes.

started a month of two ago. Everymorning it would be hart to start, it would crank then after a minute or so it would fire up. ONLY COLD. When you run it or drive it i can shut it off and turn it on, hott but never cold. I have done fuel filter, igntion upgrades. SO, i talked to a guy who told me it was the regulator which is under the plenum. After a night of removal/install still no dice. I believe it is fuel for this reason, it wont crank up so i opened the throttle blade, and squirted some fuel in there with a bottle i had and BAM fires right up. So a fuel restriction is somewhere i just dont know where. Fuel pressure is around 50 -55 cold and hot. When i crank it the FP falls a tad. Regardless i think it is either 1 of 2 things, the injectors OR the Fuel pump. The pump is somewhat new. Another weird hickup is when it is hot, if i rev it up to 4k or so it drops and it wants to die almost. Butnever does.

 

which vortec btw? I can remember my old vortec had quite a few vacuum lines. You might have a blocked line causing problems. You have EGR?

 

Sorry, the truck is a 1998 GMC vortec 305. "spider" injection as its called. I called it "shitbox" injection.