99 Blazer Crank No Start Issue
 

Hey, all. I have a 99 Blazer that worked well until a couple of weeks ago. I let it sit for a few days until I could get some time to change the brakes, but when I went to start it, I couldn't get the engine to turn over.

Previously I did notice some issue with accelerating at low speeds in wet weather (it got a little rough when it rained), but nothing else of note.
It's a steady cranking sound, but there's no start. I already tested the battery, the ICM, and today tested the fuel pump. The starter appears fine, and the alternator is good. I tested for spark at the first spark plug and it was fine. It also doesn't appear to be the ignition switch or a fuse. It's been below freezing for a month here so I thought it might just be cold. But heating up the engine with some block heaters and a hair dryer didn't make a difference either.

I suspected a fuel pump since it's a common issue and I had some trouble with it kicking on earlier in the fall. When I pressure tested the fuel pump today, I turned the key to on and the gauge went to 56 psi and stayed consistent after I turned the key off for 5 mins. So, no fuel pump issue? I can't actually start it, so I couldn't do the complete pressure test.
With this result, could my issue be the spider injectors, or does the pressure test eliminate that as an issue? I've seen a couple of articles that suggest a good pressure test means no spider injector issue, but I don't want to eliminate it without double checking.

I'm thinking at this point that it is either an injector issue or a distributor problem, but I'm pretty stumped. And annoyed that I don't have my 4x4 for the snowstorm I'm getting tomorrow.
I would love advice about what else I could try. My last resort is to take it to a mechanic since that's probably going to put me out a good grand. If I can diagnose the issue and get parts, I have access to a garage to fix it myself.

Should I start replacing potential problem parts at this point? If so, which one(s) should I start with?

Any help is appreciated. Thank you!

Edit: I just did the fuel pressure test again, and it went up to 56 psi at first, but slowly dropped with the key on to 54. I turned off the key and it slowly dropped to just under 50 in a few minutes. So maybe it is the fuel pump? It is also less than 15 degrees F outside right now.

If you're testing pressure at the service port, you're testing the whole system, including the injectors and regulator. To test only the pump, you will need to separate the pump from the rest of the system. Either at the fuel filter, or pressure side of the pump will work.

When testing just the pump, pressure should be 80-100psi, and hold for at least ten minutes. Tons of threads on here detailing the specs.

At the service port, I want to say 55-62 psi? Can't remember exactly. Should hold pressure for at least ten minutes as well.

If found from my own experience that while it's supposed to hold pressure, the truck will run even if it doesn't, but the pressure has to be there while the pump is running. Not holding pressure is a sign something is wrong, but shouldn't prevent the truck from running.