OK first let me say that this only happens when it is warm outside or seems too however it does not happen everytime. My 86 K5 will sometimes just act like it has run out of gas. It will start spuddering and jerking and finally just quit. In about a hour it will finally start back up and run long enuf to get me home. Needless to say I have been stranded more than once. I thought maybe it was getting vapor locked because who ever had it before me had added braided steel line bettween the pump and the carb with two little small glass filters one at the pump and then another on up the line. I thought maybe the way these were routed causes them to get hot and turn the gas into vapor or maybe that these filters are too small. When it has done this I have pulled over right before it quits complely and the gas is just barely coming up into the top class filter. I also thought it could be that the fuel line because it has be replaced with rubber line instead of the steel and maybe in a hard pull it kinks up or it could also contribute to the vapor lock idea. I even thought it could be a bad fuel pump but there is not gas in the oil and like I said it doesnt do it everytime I drive it. If you guys can give me some help I would appreciate it. I am a poor college student and have have to do most of my wrenching myself. Thanks guys

 

Welcome to the forum,
check the fuel pressure it may be that the pump is getting weak

 

There might be nothing wrong at all. I have fought the same problem all summer in my 79 blazer, and have yet to find a real solution. Only one real problem remains. THE FUEL ITSELF. After some reaserch have found that the new gassoline formula with 10% or more ethanol has a much lower vaporizing point than our good old non"green" fuel. Our older trucks were never realy designed to have this. sure they run and run well, i replaced everything from the tank to the carb and it still happened. All I did to fix the problem was to keep all lines and filters as far away from heat as possible, and use heat sheilds or split heater hose over those glass filters( I have 2 as well ). GOOD LUCK!!

 

Make sure there's alittle gas in the carb.