Gonna throw this out there for all my fellow gearheads to ponder. I've got an 06 Equinox LT 3.4 FWD. A few years ago the fuel pump failed and was replaced by a local shop. Normally, I would've done it myself but simply didn't have the time. Fuel pump was fixed but ever since that repair the car has had a different issue.
When fueling the car, if I add even 50 cents more fuel after the gas pump shuts off, then I get the following issue: The car starts fine, but once I pull onto the street and start driving, the engine beings chugging and spewing dark smoke out of the exhaust. The engine will rev back up then almost die again... over and over. After about a mile or so, it stops and runs normally. I have no idea what is going on, but I'm guessing there is a valve somewhere that is hung open and flooding the engine with fuel. Again, it only happens when I fill the car up. And yes, I know to never fill the car past the "click" at the pump. But I know I'm not the only one who rounds up to the nearest dollar... or quarter or fifty cents or whatever. I don't do it anymore because of the problem, but it needs to be fixed. Y'all throw some suggestions at me. Thanks!

 

no codes or engine light? the symptoms sound like the evap purge solenoid may be stuck open but the smoking isn't normally part of that. Easy enough to check just unhook the line that comes from the canister and with the engine idling see if theres any vacuum at the purge solenoid where you unhooked the line. Disconnect the electrical connector to be sure that its not being commanded open.

 

Thanks Cleveland. Yeah, a friend of mine said something about the purge solenoid but I thought check on here first. I'll give that a try and see what happens. Thanks again.