Vapor Lock or Fuel Pump ?

So I have been busy lately adding N/A mods to my truck. Wrapped up the SABM earlier today and went for a spirited drive. 10mins into my drive i floor it and immediately followed by a loss of power and then it dies.

As I coasted it to the access road I'm like wth. I had just topped off the tank with 93. No CEL, smoke, noise, or anything. I tried to crank her and she starts then dies right away. I continue to look under the hood thinking I unplugged something by accident and all is secure. I try cranking 3 more times and feather the throttle and it stays on but idling around 400rpm and any introduction of gas pedal and it bogs and tries to die so I let it idle and put into drive so I can pull into a park up the street. I basically idle drive into a safer area than the access road.

I turn it off and look around again, by now I'm thinking the worst and i possibly hurt my engine. I crank her again and she idles better so I give it some gas and it sputters but clears up. Baffled I decide to drive it home slowly and she behaves like nothing happened. Get to my house and take the gas cap off to a loud hisssss.

Would be a nice reason to install a FFV pump but would like to know for certain what happened. Anyone have this happen ?

 

On modern cars, vapor lock is almost non-existent. Back in the sixties and seventies, GM went through a spate of vapor locking problems that led to a TSB for installing fiber insulators under the carburetors (that's how old this problem is). When the environmental police forced manufacturers to go to higher underhood operating temperatures, they were forced to get smart about the vapor lock problem. Low gasoline quality can also be an issue (high* out-of-spec Reid vapor pressure = vapor lock). The standards are now pretty tight for gasoline as well.

I suspect you have low fuel pressure. It could be the fuel pump, but the whole system has to be diagnosed.

*Edited. High Reid vapor pressure = increased volatility

 

Thanks for the feedback


Just went for a drive and CEL popped up with lean codes P0171 Bank 1 & P0174 Bank 2

Leaning towards the pump but will do some more diagnosis before heading that route.