i own a 2000 chevy blazer 4.3,late last summer when it was in the 80s 90s outside my truck would get a vapor lock type feeling.it would start to spit spudder and then die.once it cooled off it fired up and ran great.this happened about 5 times until fall and winter came,then it ran sweet. now spring is here and its getting warmer out,back to the same ole same,but now its worse,it seems to die out around 10-15 miles of driving no matter what the temp is. it even does it at an idle now if you let it just sit and idle for about 15 min.when it pooped out once, i dumped a lil gas in it and it fired up for a few secs mybe 8 secs. then it pooped out again.let it sit awhile and bam fires up runs great. i have noticed that the pump is loud when starting at times then the next time you start it you cant even hear it. i got so mad the other day i took the plastic cover off the gas tank and put my ear up to it and listened to the pump.it had a nice quite whistle to it. then i started to bang on the tank and all of a sudden the pump started sounding like a freakin weed whip! it got real loud and growley. it did not stall thoe until i put my foot on the gas pedel. then it pooped out. am i safe to say that this is the fuel pump? i changed it 2 yrs ago,but it never did this until i changed the pump.started out slow.just wouldnt restart after long drives but only had to wait 5-10 min for restart,not a huge deal at the time.then it became the stalling during hot weather,wait 30 min to an hr. start up run great. now it does it at idle long drives hot weather.last year i changed, plugs wires cap rotor hole new dist. coil(2) icm (2) crank sensor(2) cleaned egr valve real good,changed the fuel pressure reg. and fuel filter(2) and all three o2 sensors.due to the awsome fuel prices we have my tank is hardly ever filled past half tank.i herd that that is not good for an after market fuel pump. it this true? plez help....thanx

 

in my opinion afterarket fuel pumps are a bad idea in the first place. ive had my share of problems with them until i bought a delco. sounds to me that there is some kind of thermal breakdown happening with your fuel pump. it is a bad idea to run around with little gas, your pump is cooled by gas in the tank splashing around. when there is not enough gas the pump isnt cooled as well and tends to wear them out quickly. i would check your fuel pressure before going too much further. maybe double check wiring from the pump as well.

 

ok ill try that.thanx

 

MY 92 has started that . I can drive it for 25 or 30 miles and it starts acting like its running outa gas. I can put it in netural and it will smooth right out. Whats up? Fuel pump also ?

 

Probably fuel pumps. Delphi is the suplier to Delco for their pumps so you could go with one of them. My 94 4.3 Code W pump was intermittant. Ran fine when I had it out of the truck then banged on the tank a little and it quit. ood thing I hadn't put the tank back in yet.

 

How about ignition module?

 

I had exact the same symptoms with my '98 4,3. And finally I found a problem - the is a plastic corrugated tube, it goes from the fuel pump to the upper part in fuel sending unit in fuel tank. That plastic tube concerned the walls of the unit, and in was a small-small hole in plastic tube. Sometimes that hole touch the wall - during that u can start the engine well, and sometimes fuel run through that hole, and the fuel pressure goes down - engine does not start. I replaced plastic tube just with a piece of fuel/oil resistant rubber tube (cause I'm living wery far from ORIGINAL parts((((( -- now engine starts well, and run fine!
I'm talking about this:
http://cgi.ebay.com/ebaymotors/New-C...item1e5dbd452a

 

Got the 92 s-10 fixed . It was the fuel pump. The sending unit was bad also. Runs fine now.