What damage or problems can overfilling a gas tank cause?

Question

I overfilled the gas tank on my 2014 Subaru Outback when the pump nozzle malfunctioned.  What damage can this cause to the evaporative emissions system? Can it make the car hard to start after fueling? No engine codes are currently set but I occasionally get a lean left bank code (P0171) at idle when engine is hot.  Code is easily cleared and reoccurs only infrequently.

Answer 1

P0171 Fuel trim lean Bank 1

Overfilling the fuel tank can and does cause the hard to start, but that just when its full, But if you are setting a P0171 when the engine is hot and occurs seldom, A MAF (mass airflow) sensor would also do this. Try doing a MAF cleaning.

Comments

Thanks. I think you are probably right. I could not figure out how an overfill could cause a lean condition. The MAF certainly could.