alright guys i got one maybe to stump ya. lets start with i have 2002 chevy blazer LS 4dr 4wd with a 4.3 vortec that has almost 219 on it. just recently took it to the shop to get an alignment and some new tires. upon sitting at the shop waiting to be brought in for service, i get a call saying my fuel pump **** out. $650 dollars later i have a fuel pump. they told me that whoever did the fuel pump last (which was late 2013, dont know why this thing ate that pump but it did) they broke the quick disconnects on my hard lines and hose clamped bulk hosing to the pump. well fuel pressure hasnt blown them off yet so i guess its fine still kinda stupid. so im driving this thing for about 4 or 5 days and it starts to not want to start right up. it would roll 2 or 3 times then fire. well as the days when by, 2 or 3 rolls turned into 4 or 5. then finally on friday morning i killed the battery trying to start it. got back home from work, it had been sitting out in the sun all day, and it fired right up! the battery was dead just 8 hours prior and not charged at all. so saturday i go out at 11 oclock and try to start it, it no want to fire. so i left it alone for 2 hours. went out, fired right up. drove it around for 5 hours got an oil change, on my way home going up a pretty long hill i noticed that it had no power and towards climbing higher RPM it threw a P0303 Cylinder 3 misfire code. got home and parked it, got picked up went out with friends, got home at 2 in the morning, pretty chilly and this thing had enough time to get cold and not want to run, BUT!!!! it fired right up. today went out to start it it didnt want to go, even in the heat, so i dumped a bunch of starter fluid down the throttle body and it fired up with a little weirdness BUT IT STAYED RUNNING, i dont understand what this thing is doing. changed the cap and rotor and the plug wires. spark plugs are pretty new changed then 5000 miles ago havent checked them but will i do know they can go bad with bad other **** but if anyone has some insight please let me know. just dropped over 2 grand getting this thing back on the road and now its sitting in my garage

 

hello, my truck did that during winter. still to this day I don't understand what happened as once it started it has been running well. Now as far as I know I have read that blazers are picky about fuel pressure. I will check it specially as soon as the problem occurs as maybe the fuel pump is getting weak and your not getting enough pressure to start the truck. also look at your dist cap for corrosion and /or wear and tear. when I did my trucks intake manifold gasket replaced everything with brand new parts and that's when I realize my distributor cap was worn pretty bad.

 

well the pump is 2 weeks old and the cap is 1 day old so idk

 

just because they are new don't mean they are good - start with fuel pressure check - per captain hooks instructions - do a search you will find them

 

so the struggle has been real, but i found out i have a weak pump, or at least im pretty sure. hooking up the fuel pressure gage behind the the filter after i pulled the filter off would read 50. which should be fine but thats the bare minimun. hooking it up at the shrader valve in the engine compartment would give various numbers as i primed the pump but would sit at 50. when it was at 50 it would not start but as we pressurized it back up it would start

 

Glad your getting close or found the problem, those psi are pretty low and as it gets colder( not sure your location) it gets worse. you said the pump was recently replaced right? Can you still return it as faulty unit? You said you checked the pressure before the filter as well correct?