2001 Blazer starts fine runs 4 to 5 seconds then Dies
 

Got a bone stock 2001 Blazer. Its starts fine, runs about 4 or 5 seconds then dies. I checked fuel pressure with a rented auto zone gauge set up and with key on engine off i had 50 - 52 PSI. After starting I was seeing about 48-50 PSI and it stayed in that range after shutdown with no noticeable bleed down. From what I've been able to research those pressures seem a bit low.
I don't have a check engine light nor am I reading any codes With the ODBII reader i borrowed from a friend. I did change the fuel filter on the the advice of another mechanic friend with no change in symptoms.
I've done a visual inspection of the mas air sensor and to the untrained eye it appears fine (no mouse bones or feathers) and clean. So any help you all could give will greatly appreciated.
Thanks For Your Time.

You need to determine whether or not you're getting ignition spark right after it stalls. get your hands on an "Inline Ignition Spark Checker" and then after it stalls next time then pull the coil wire off and connect the Inline Ignition Spark Checker onto the coil on one end of the tool and the coil wire on the other end, have someone crank over the engine while you look for a strong coil spark. If there's to visual spark or a weak spark then have your ignition control module tested and or replace it. You could also have the coil checked at your local autoparts store at the same time.
https://blazerforum.com/forum/attach...ine=1406955811
https://blazerforum.com/forum/attach...ine=1406955811
Coil and ICM are mounted on the same bracket.

Checked spark with Inline Ignition Spark Checker, spark is visible and strong. Problem still exists.

New development on this one...since unplugging and plugging the coil wire back in several times (to install test light) now it will start and if you hold throttle just off of idle it will stay running, but once put in gear, it will not throttle up more than 1200 to 1500 RPM's.

A simple cheap thing to try might be the fuel filter.

fuel pumps bad. these things eat em,and they must but at least 58 psi to run.

buy ONLY ac delco or delphi pumps. other cheap aftermarket pumps die in these blazers within days or weeks....ive gone through too many.

Thanks again for the help. I should have put in the original post that I had changed the fuel filter. And I was hoping to avoid dropping the tank to change the fuel pump but it looks like that's where I'm headed in the morning.

So changed the fuel pump and been driving it a couple days and it looks like a good fix. I was a little worried when I first started it up though; after bleeding air from the system; and starting it up it ran pretty crappy for almost a full minute!
My question now is, is there a sensor on the fuel system that has to tell the computer (ECM) that the pressure is good and its ok to run? If so that would be some handy info. To have in the form of an ODBII code as I got nothing in form of any type of code when this problem started.
But thanks again for all the help I appriciate the time and effort. Hopefully I get another 100,000 miles out of the little Blaze!