07 Tahoe 5.3 I see that somebody replaced new evap box canister, evap solenoid with line filter to gas neck, also new purge valve solenoid. After 1 gallon fill up then hard to pump take forever to fill up. What is the cause. I pulled gas neck hose to tank it look clean no clog, what it other most common.

 

evap canister is clogged

 

Same problem with my 07 Tahoe 5.3, #1 cause = topping off the tank.

Replaced and installed the following and I have not had a problem since.

Vapor Canister Vent Valve ACDelco GM Original Equipment 23481275
AC Delco GM Original Equipment Vapor Canister Vent Solenoid Harness 19257603

 

I fixed mine by shorting the vent hose because it had a kink in it, cut 3" off and it fills up at the pump wide ****** open!

RT

 

Today I replaced whole new vapor canister, evap solenoid and purge valve solenoid. Still doing problem same. Pull tank down. Check all lines. No clog at all

 

Did you try to blue the lines out with compressed air? My culprit was the vent solenoid on the top of the gas tank

 

pinched line. I dropped my tank 3 times after installing a pump and finally came across it. when you raise the tank it is probably pinching on one of the crossmembers

 

Take the bed off and survey the lines.

6 bolts, pull the tailights out, have a friend help pick it up.

 

Easier to disconnect the 2 big plugs under the back of the bed than take out the tailights.