99 Blazer- Has spark and fuel but no start

Had 99 blazer into our repair shop. He had it two weeks trying to fix a problem we had starting truck and gave back to us as some days it started and most it does not. He said it had fire and fuel and did not make sense. He gave it back saying he just can't figure it out and time for new car. I cannot afford one as husband has serious medical problems. Over last year we have had alternator, starter, fuel pump/filter and distributor replaced (used distr), tune up, and air filter. Also battery reads good. Cleaning out things like fuel injector additive to gas etc. seemed the next step as at times when it feels like it is going to catch and start, it may sputter some as if moisture in gas right before it catches after immediate next time or two turning and trying. Then last week another mechanic cleaned out carburetor and did a few things like fuel injector cleaner in gas and taped a loose wire. Thought we had it but the next day it would not start again. As we have tried over and over battery wears down seems sooner the last month. It cranks over and over but just will not catch to start. When problem started it would start after 5-6 tries of turning, then as we went on it could take 20 times or sitting over night. For awhile we thought it was cold weather issue since it was cold when problem started and on warm days we had more luck but it has been warm weather for awhile now and no difference. Any other ideas to help? Appreciate any input.

Sounds like a lack of fuel pressure. Must be 60psi MINIMUM to start.

Was a fuel pressure guage ever put on it to observe fuel pressure? The fuel pressure has to be a minumum pressure for the truck to start. I keep forgetting what pressure it is, but I am sure someone will chime in, or you can search it on here to find the exact value.

If you have proper spark, strong blue constant spark, then only next thing you need is fuel, and that has to be at spec or it won't start. Even if the fuel pump is still working, at may be weak, so you need the guage on there and you need to watch it very closely. Keep it simple, cause its usually always the most simple stuff that goes wrong.

Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post-back fuel pressure readings.