I would think the .9 is the correct resistance. 350 ohms is way too high. .9 would be a 13 amp draw and 350 ohms would be under an amp. My fuse is a 20 amp fuse which would be correct for the .9 measurement. If the actual amp draw were under an amp then the fuse would be a lot smaller to protect the loads it supplies.
I personally think you're looking in the wrong direction. You have been looking at the tank, pump, filter, lines,etc. Maybe you should look towards the engine. It's highly possible that you have a bad fuel pressure regulator, fuel pressure sensor,or a bad injector(s).

 

Basically You're right in this case. One Ohm +/- gives 12amp current. That is 12V*12A=144W for the pump. The other one is 0.4W (dirty commutator or worn off brushes?).

But beware, when it comes to bigger electric motors the more significant role plays the inductive type of load than resistive. As, for example, You may have a motor in good condition with a winding made of a thicker copper and would read a lower resistance, while inductance remains same. A coil store energy and when You disconnect the power, the voltage on coil ends will surge, etc.

 

I've thought about that. But if that were the case, wouldn't fuel pressure continue to be low, even with a new pump? Every time, after I replace the pump, fuel pressure is right on spec, and the truck drives well.

Don't get me wrong, I know there's something else going on. But I don't want to just throw a $200+ injector/regulator on without some way to diagnosis it as being bad

 

A common fuel pump has the check valve, so even if the fuel line is clogged, the flow goes trough it. Neither You can affect the motor electrical resistance (340 Ohm case) by poppets or fuel pressure regulator. Bad injectors would come out on a fuel trims test...

How did You measure the pump resistance? Directly at terminals? I mean, I used to say there are no miracles in engineering, but Your ride ... seems to be cursed bro...

 

Pump resistance was measured at the terminals, once the pump was removed from the tank and sending unit.

The 0.9 ohm was the new pump that has gone bad, the 350 or so was an old, questionable pump I had laying around that had been replaced a couple years or so ago

 

I haven't been dismantling the blazer pump yet, but if that's mechanically possible try giving the old one (340 Ohms) some turns, maybe the commutator got oxidized and it will eventually kick in.

 

 

All I have access to is the info on this website.

The question I've been asking for years now, is why are my pumps failing lol.

 

I agree. I'm by no means am a mechanic. I'm just trying to throw some ideas your way. Many years ago I had a fuel pump in a car that kept crapping out. I took it into a shop and they had a difficult time figuring it out. They finally narrowed it down to a wire underneath that had a nick in the insulation that would hit against the body and take out the pump.
Keep in mind that a regulator or sensor could be crapping out after working a while. Since I'm not a mechanic I will take mine into a Chevy dealer and have them figure it out. If it was something I could fix then I'd pay them the diagnostic and say see ya later...

 

It's possible to dismantle the pumps, but they aren't ever going back together after. They're press fit, so they don't come apart without cutting the case in half.

I rigged up the old one (350 ohms) just for grins and energized it. It runs, but sounds pretty rough.

I ordered a new Delco pump, and new rear fuel lines. Also, my buddy has the tools to replace connectors in westherpack connectors, so I'm going to rebuild the sending unit connector.

I'm running out of ideas