can evap system leak cause bad gas milage in 2002 f-150 on 2002 Ford F-150

can evap system leak cause bad gas milage in 2002 f-150

1 answer
Yes, it could. i.e. a disconnected vacuum hose or a stuck open vent solenoid will let extra -unmeasured- air into the manifold and since the ECM will adjust to the perfect air/fuel ratio it will keep the injectors open for a longer time, which results to lower gas mileage..
I don't know if this is the problem in your case, but it can happen for sure.

Zee