Q: Q: P0171

asked by on

Its an 02 f150 lightning i put headers and cats on it new 02s new coilpacks new spark plugs all the intake gaskets and supercharger gaskets new vacuum lines new fuel filter and im getting ready to buy a new ecui even did the line that comes out the back of the intercooler housing thats most common to give u these codes i just keep getting the p0171 and dont know what else to do just wondering if you might know something else i may have missed

My car has 76000 miles.
My car has an automatic transmission.

The cause behind diagnostic trouble code P0171 is easiest to find by looking at the secondary firing patterns on the Bank one cylinders. That will confirm if the too lean condition, that has caused the code to set, affects all cylinders in the bank. If not all cylinders are affected, test for defective individual fuel injectors. However, if all cylinders are affected, you would test, in turn: the fuel pressure regulator, fuel pump pressure, check for a clogged fuel filter, vacuum leak, faulty oxygen sensor(s) and faulty mass air flow sensor. Rarely, the cause will be a faulty powertrain control module. If you want these steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a check engine light diagnostic - code P0171 and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: There is no power and is shaking in overdrive.

The Mass Air Flow sensor (MAF) may be dirty and causing the throttle position sensor to act up. Remove the MAF and clean it with electrical cleaner and then put it back on. Check all the hose clamp connections to...

Q: Q: AC only blows hot air

Hello. We will be happy to assist! To diagnose an AC concern, I first suggest checking the refrigerant levels as it is the most vital component to the health of the AC system. Then, a technician should attempt directly switching...

Q: Car shaking and dying

The battery will drain quickly when continually trying to start the engine, if the engine doesn't run long enough for the alternator to keep the charge of the battery. The stalling may come from an issue with air metering, or...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.