Another 99 Tahoe cranks wont start post

[BasicPhreak]

I know there is tons of this post out there, but none seem to apply to my problem.

99 Tahoe.
Ran fine, battery went bad. (Had it tested, not assumed). Well before we could get a new battery in it, we got a really bad cold snap here in Montana. Temps 10 below zero for days. So it sat for 2-3 months.
Got a new battery in it. Cranks and acts like it wants to fire but doesn't. Put some HEAT in the gas tank. But without it starting it doesn't really do a lot of good.
I did a professional diagnosis on the fuel line. (i.e. I took the cap off the fuel rail and pressed down on the Schrader valve.) It squirted fuel. I had my Mom crank it while I was pressing down on the valve and it squirted more fuel and then somehow blew up in my face. I had the Air Box off the throttle body, so I am wondering if it backfired. I still have my eyebrows though. Mark that for a win.

Going to try and change the plugs next, but the part that gets me is it ran just fine, aside from the battery going bad. Change the battery and it doesn't work now.

[Tech II]

Gee there is fuel coming out of the schraeder valve, so pressure must be good...

The fuel pressures are crucial......

You need to put a gauge on this......you need 60-66 psi......below that, just a couple of PSI, and you have a hard start....

What I would do, is try replacing the fuel filter first.......

Also check that the fuel pump ground is clean and tight....

Also try spraying carb cleaner into the intake, before attempting to start the vehicle....If it starts if you spray first, your fuel pressure is borderline......I would replace the fuel filter before replacing a pump.....

Also, is the vehicle up to snuff, tune up wise?

[j cAT]

it was reported on the forums there are professionals that did the fuel test you just performed ... to know for sure you must measure the fuel pressures . should be key on eng off 60psi and higher .. that is good it will start if its 53 psi but not as good and a bit low.. below 52 psi hard starting .. sitting for months with little gas in tank is not good .. using the pressure gauge like I have it has a dump valve so I can flow the gas in a container to observe the flow and the color debris .. if really cold can be water in fuel filter its frozen ,,, stupid stuff like that... the other cause could be a vacuum leak ..