Let me tell u how it started. I was pulling a trailer for my gf parents and when i got back to the house i went to drop it but i was parked on a slight hill. To keep me from rolling back into when i took it out of gear i gave a slight punch to the gas( nothing hard) but it was like the blazer stalled a lil but didnt die. IT idled fine. I went to drive across the road to my house but i would hardly make it. Any time i gave it gas it would run super rough but still idled fine. I then replaced the fuel filter and nothing. Then i replced the fuel pressure regulatior and nothing. today i replaced the fuel pump and nothing. If u pour gas in the intake it will start up and run off whats in there but once its gone it dies. When i try to start it it backfires and pops. I even hear like a popping in the gas tank almost like someone pounding on a bucket. I am lost now and dont know wear to go. What are some sensors i should check and were would they be. Whats the thing that hangs above the rotor cap that has to vaccums hoses attached to it. I am really hoping to get it running this weekend becasue the head gasket in my acrua decided to blow thursday and i really need a ride to work. please any help would be great thanks.

 

Popping coming from the fuel tank could mean that you have a problem with the EVAP system not properly venting. Will it run if you remove the fuel cap?

 

lol funny u asked that becase i seen that i was trying to start it with the without the fuel cap on. so i put the fuel cap on to see if it was a pressure issue. I am so stuck. If it will run by putting fuel in the intake but not crank on its own take out the chance of any sensor being bad. but no it still wont crank with the cap off

 

My 96 did the same thing, ran fine one minute, the next it would run real rough if I gave it any sort of throttle. I replaced fuel pump, fuel pressure regulator, tank vent valve and an injector with a bent pin with no sucess. I did a warrenty return on the fuel pump because it would only put out 55 psi with the key on, and its supposed to be 60-66. Since fuel pressure drops when running, and the pump never put out correct pressure I returned it. When the new one arrives I will update you on whether or not that fixes it.
Have you checked fuel lines for leaks/blockage? What is your fuel pressure at the port when you turn the key on? It definitely sounds like you have a fuel supply issue. The 96+ fuel diagnosis post can help you troubleshoot some more.
Let us know if you figure it out...

 

i am going to auto zone tommrrow and getting a pressure gauge and will check it. when i turn the key on and it run for the few seconds what should it read. Also two of the three nylon hoses that run from the fuel pump to the hard metal fuel lines seem like they had a slight kink. Could it be the injectors.

 

When the pump runs for the 2 seconds when you turn on the key, your pressure should be between 60-66psi and should remain there. If it drops, you have a leak and need to track that down. Those three hoses in the back have that nice 90 degree bend in them, but if they aren't leaking its probably fine.
You can pull the electrical connector off the top of the upper intake manifold and look down inside for any bent pins (if you have CPMFI) or pull your spark plugs and check for lean conditions or fuel soaking to see if you can narrow down a problem with the injectors.
As a note, put your vehicle type in your signature, it helps get that info out there, as there are some differences in the models that can help with troubleshooting...the advice I am giving is based off of my experience on my '96 and the factory service manual.

 

Ya every time i walk away from the computer i think of something i forgot. Its a 2001 4door 4x4. Also if its any help it seem that all it wants to do is backfire. Either it tries to shoot a flame out or its like a swoosh of air.