I think im having fuel delivery problems? ?help?

My 98 blazer has been acting up after sitting for period of time (cold) and when i would start it it would take 5 or so time of me cranking the engine over. That or sometimes I would turn the key on/off on/off on/off numorous times rapidly and it might start on on the 3rd time I would crank the engine over. My brother replaced the fuel pump last year, and said he replaced the fuel filter pretty frequently when he owned it. Now it wont even start unless I feed gas in through the intake and the blazer has the CESFI fuel injection system. Anyways when I pour in gas it will run for maybe two minutes with really rough idle jumping from around 1500 rpms to 3000 rpms than dies. Any ideas? oh an fuel pressure with key just turned on is around 50psi (its suppose to be 55-61psi) but is the 5-10 psi I dont have a big deal? and when I get it running, at first it jumps to 60psi which it should lower 3-10psi from the intial 50psi. :confused:

Yes.
Even a couple of lbs low can keep the injectors from squirting on a cold start.
You fuel pressure specs are 60-66 on that year with a V6.
You need 64-65 lbs on cold cranking.

The only true test on a fuel pump is to check the direct fuel pressure from fuel pump.
A quick test is to block off the return line and see if fuel pressure comes up to 75-85 lbs.
But do not run the pump at full pressure very long.
Also when testing fuel pump and pressure you need to tape a gauge to outside windshield or outside mirror and drive it on the road for 20 -30 minutes
until the pump gets has run a while to check for a pump fading out after hot.

Hard to start cold and fuel pressure testing guide line.
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.
If pump has full pressure with return line blocked and low pressure without it blocked most usually the fuel pressure regulator is leaking or not holding 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 in system.
Post back fuel pressure readings.

Well thank you for the proper Specs. and advice. Today i decided to check the pressure before it went through the fuel filter and because I used a rubber house with a T-fitting so i could hook up my gage I plugged the outlet of the T-fitting as if I were stoping the gas from going to the filter I rigged a plug for that end and it had a decent leak. But I still got a 54 psi. reading with the leak there instead of the 50psi. through the ?stradel? valve or w/e by the intake. During that test I accedently turned the engine over and it started?:confused: with no fuel running to the intake? and yesterday and earlier today it didnt even get fuel when the lines were connected. Y is that?
But because the 54psi reading right before the filter I went and bought a new filter and it started!
yet the fuel pump now sometimes wont prime - (((and the engine wont start right away, but will eventually)))) - when key turned on but the pump always turns on to relieve the pressure after turning the key off??? is that fuel pump, battery, relay...?
Have I done things right so far?
Thank you,
Greg

Well thank you for the proper Specs. and advice. Today i decided to check the pressure before it went through the fuel filter and because I used a rubber house with a T-fitting so i could hook up my gage I plugged the outlet of the T-fitting as if I were stoping the gas from going to the filter I rigged a plug for that end and it had a decent leak. But I still got a 54 psi. reading with the leak there instead of the 50psi. through the ?stradel? valve or w/e by the intake. During that test I accedently turned the engine over and it started?:confused: with no fuel running to the intake? and yesterday and earlier today it didnt even get fuel when the lines were connected. Y is that?
But because the 54psi reading right before the filter I went and bought a new filter and it started!
yet the fuel pump now sometimes wont prime - (((and the engine wont start right away, but will eventually)))) - when key turned on but the pump always turns on to relieve the pressure after turning the key off??? is that fuel pump, battery, relay...?
Have I done things right so far?
Thank you,
Greg

For a cold start you need 64-65 lbs pressure to injectors.
Go threw the fuel pressure test as outlined.
Good luck