Happened after fill up with Mobil gas, which I use regularly and from same station
Engine suddenly idles rough and engine light is on after gas fill up on 2004 GMC Yukon
It sounds like a vent valve is staying open allowing gas fumes into the intake manifold when you are refueling. I causes an excessively rich mixture when you go to restart the engine.A scan tool is first needed to retrieve codes stored in the computer of your car and that will lead to where to start diagnosing the problem but it will be an evaporative emission issue.
Someone recommended that I use a fuel additive to clear this. Something called Marvel or the like. I have not changed the fuel filter and truck has 46k miles.