It causes improper fuel pressure/ vaccum with the cap off. when the cap is on the system is sealed properly. I have seen some trucks throw the engine light when the gas cap was left off for to long of a period.
not around here lol we got dumbasses that run over the tankers hoses while fillin the tanks up that blow everything up
I don't think I've ever left my vehicle on while getting gas before. Sent from my iPhone using Tapatalk
Ive heard you're not supposed to keep it running, so I always turn it off and never questioned why. Sent from my iPhone using Tapatalk