check engine light came on and message appeared that the gas cap needed to be tightened. had diagnosised to determind gas cap was no longer sealing properly- replaced gas cap, but check engine light still on
"tighten fuel cap" persistent problem, replaced cap, replaced tank vent solenoid (that fixed the slow fuel fill problem). Cleared faults for about a month then get a periodic "tighten fuel cap" and check engine.
MIL light comes on right after I fill gas tank and drive at speeds over 70 MPH. New O2 sensors, New air filter, new spark plugs, new plug wires, and I still get a P300 trouble code. (Random multiple mis fires). No help from Dealership other than an offer to TRADE IN TO buy "THE NEWEST CROWN JEWEL". Well, BS to that...
I got a message on dash telling me to tighten the gas cap. I thought this was strange sine I hadn't gotten gas for about a week. Anyway, I tightened it for chuckles. Next day, I got the same message and did the same thing. Then I got the indicator light for the gas. I called on-star to do a diagnostic system check. They said tighten the gas cap and if the problem persists, go to the dealership for service.
1)"Tighten loose gas cap" warning message came up twice in the message display.
2)"Engine light" illuminated on the dash cluster.
3) Gas cap WAS loose, re-seated & tightened cap - haven't replaced, yet. Will recheck this PM.