We just purchased a 2012 GMC Acadia, has ran fine cranks fine UNTIL we put gas into it. It then didn’t want to crank unless you held the gas pedal down and it would catch. (Done this twice now) We did add sea foam to the most recent fill up thinking maybe trash or old gas from sitting etc. This only happens when we put gas into the vehicle; once it catches and cranks I can shut it off and it cranks like normal from then on. (Yes we did make sure we used correct gas 
) Any ideas what this could be it’s been wracking our brains to the point I don’t want to go get gas when it needs it next time Thanks for the help
The most common cause for this is a leaking purge valve in the EVAP system.
When refueling the vehicle, the purge valve should be closed.
If the purge valve leaks, if forces gas vapors into the engine when refueling which creates a flooded condition. This then requires holding the gas pedal to the floor to clear the flooded condition and the engine starts.
If the Check Engine light isn’t on, wait and it will eventually turn on.
That’s if the Check Engine light works.
Tester
1 Like
Thank you I appreciate the help we will look into that !
Concur w/above, good chance the faulty purge valve theory correct. Another possibility ---- if the above doesn’t pan out — is the evap canister is faulty. The carbon particles, which should be trapped inside the canister, can sometimes dislodged and get sucked into the engine, especially after re-filling. Be sure not to overfill the tank, as that can cause this sort of canister failure. On a 2012 it my be designed so that it is impossible to over-fill the tank.
Thank y’all for your help replaced the purge valve and it works perfectly !
Thank you again