i have a blazer that when it sit's overnight it takes a long time to start.
and once it gets hot it will hesatate and want to stall when you pass 25% throttle if you turn the truck off and then restart it will work fine for a couple minites and the do the same thing. my fuel pressere seems low its at 50 and drop's to 45 when reved and a little lower when it hessataess then fluctuates about 5 psi

has had the spider and pump and filter replaced in the past two years but the truck sat for alot of that time.. pease help also the fuel pump has 10.5 volts at idle but when you rev it it jumps for 12.5 and does not drop when its hessatating please help me thank you

ps also when it is hesatating if you spray start fluid in it it will rev back up like normal so i know spark is good

 

you've replaced the fuel pump, the filter and the spinder...you said it sat for a lot of the two years? umm my question is have you gave it a tune-up since you started driving it after the two years, cause sometimes a tune-up helps and if that doesn't do it try the spark plugs or the vacuum lines to the carburetor

 

Your voltage does not seem right. You should see full battery voltage to the pump. If not, then you may have a wiring problem in the +12V supply and/or ground for the pump.

Also, your pressures are very low. I am surprised that it runs. What happens to the fuel pressure after you turn the truck off?