96 blazer backfiring/stalling out

I have a 96 blazer that keeps backfiring and stalling out. I have changed 3 of the o2 sensors since that was the code that came up originally. The codes were cleared after each sensor was changed. Now it is doing this, and it isn't giving me a code. It doesn't seem to matter whether I am driving down the road or sitting still, the truck continuously dies out and backfires. I tried loosening the gas cap thinking that it was a possible vapor lock, but nothing. It acts like it is running out of gas even though it has gas in it. If it does die out and I have to restart it, without hitting the gas pedal, the rpms jump up to like 2000 and then go back down to 1000. Then it continues to sputter and fall on its face. I am so frustrated with this thing. Any Suggestions?

I have a 96 blazer that keeps backfiring and stalling out. I have changed 3 of the o2 sensors since that was the code that came up originally. The codes were cleared after each sensor was changed. Now it is doing this, and it isn't giving me a code. It doesn't seem to matter whether I am driving down the road or sitting still, the truck continuously dies out and backfires. I tried loosening the gas cap thinking that it was a possible vapor lock, but nothing. It acts like it is running out of gas even though it has gas in it. If it does die out and I have to restart it, without hitting the gas pedal, the rpms jump up to like 2000 and then go back down to 1000. Then it continues to sputter and fall on its face. I am so frustrated with this thing. Any Suggestions?

When was last tuneup?
Which engine?
Check distributor cap
Check distributor for play on the shaft

When was last tuneup?
Which engine?
Check distributor cap
Check distributor for play on the shaft
Also, Check your EGR valve for carbon. Clean and re-install with new gasket. What is your fuel pressure? Use a fuel pressure gauge and test for readings. Turn the ignition key to "run" (engine off). The pressure should rise to about 60 psi to 65 psi. Turn ignition off and watch to see how fast your pressure drops. After 3 mins. Your pressure should be above 55psi. Post back your findings.