My dad has a GM Denali. When he drives it for twenty minutes it becomes almost like it is out of gas even when it has a full tank. I am just trying to troubleshoot for my dad who is internet compromised.
Need, year, and milage to help.
You’ll need to get the fuel pressure tested to see if the pump is crapping out. It should be able to maintain 28-40 psi.
In addition he may have a saturated charcoal canister or a kinked vent line. The gas tank breaths in through the charcoal bed in the canister and if that’s clogged or the line is kinked the airspace in the tank can form a vacuum as the gas is pumped out that can make make it difficult for the pump to continue drawing gas out. When the vehicle sits after turning it off, and if the canister and/or intake line is not 100% plugged, the tank can slowly draw in air to where the air pressure reaches ambient and the vehicle can then start again…until the vacuum develops again.