P0401 1997 Ford F150 -

Question

i have vehicle hesitation and loss of power. Also have bad fuel mileage

Answer 1

P0401 Insufficient EGR flow

Insuffiecient EGR flow will not cause a loss of power if the EGR was open then yes it can cause rough idle and bad fuel mileage. Loss of power can be ignition related where the engine stumbles at acceleration. With P0401 this can be the EGR solenoid or its vacuum to the solenoid which can cause false air and vehicle hesistation with bad fuel economy.