here's the problem i can hear the fuel pump and i can turn the key on three time and then start it and it fires off for a few seconds. we can fire it off with started fluid too. i'm thinking the fuel filter is plugged but the guy that owns the blazer says i'm crazy and thinks it is the fuel pump. so i'm open to any suggestion on what you all might think it is

 

get someone under the truck to hit the bottom of the fuel tank with a rubber mallet while your trying to start it. If that doesn't work, try disconnecting the fuel filter and flicking the key forward (if it sprays fuel out it's not clogged). Just because you can hear the fuel pump doesn't mean it's working 100%. It may be worn out and only putting out a a little bit of fuel. Like say it's supposed to be putting out 55psi at idle it could possibly only be putting out 20psi.