With todays car and all of their electronic environmental controls. I've been told, when getting gas. DO NOT top the tank off. And I don't!. Why? Because it can spill out into these controls and fowl them up. Well -
I bought a used car (got a good deal) from someone that sure enough was topping it off. I knew that the cars computer was putting out P1401 and P0442 codes, which is related to the Evap System. What made it worse, was when I tried to put gas into the car, the gas nozzle clicked off. Hmmmm? After reviewing some DIY on YouTube, today I jacked the car up and inspected the system. The hose going from the fuel filler neck to the Vapor Canister was solid. Hard as a rock. I removed the hose at the canister end and little tiny carbon charcoal pellets came pouring out. I pulled the canister from the car and tested as per this video -
And sure enough it tested bad. So off to the salvage yard, hopefully this Saturday to test some used ones onsite and pick one up. One place near me has a couple for $50 which sure does beat the dealer price on a new one.
So if top off your tank, don't. Tell your relatives don't.