2002 F150 XLT 5.4 L. Throwing PO174 codes. Was throwing PO174 & PO171 but changed the fuel filter and cleaned MAF. Now threw a PO174 after 60+ miles of driving. Has a rough idle that runs 1200 rpm them drops 4-500 then will increase back to 1200. No vacuum leaks PCV hose is good. Any solutions?

Hello Randy,p0113 means that Intake Air Temperature Sensor 1 Circuit High,p0102 means that Mass or Volume Air Flow Circuit Low Input.You can read this PDF,Diagnostic Trouble Code Table .

please go to : repairpal.com/obd-II-code-po171-and-PO174 FOR MORE INFO, good-day!

This is a tough one could be mass air flow sensor ,oxyegen sensors,a fuel filter. a vacum leak, a pcv valve if i missed anything just google po 171 &174 look for fix ya this issue has been addressed many times first check the vacum lines includeing the line on the pcv valve for cracks or splits in the lines .I would do the fuel filter if it hasnt been changed in the last couple of years , if still a problem the MAF sensor if your happy with my advise please leave me with great feedback

Your still lean on both banks

Either the oxygen sensors failed or slowed
down & set a code or you have vacuum leaks

When ever you remove an intake-- you smoke it before
& after the job-- to avoid vacuum issues

Fuel Trim may give you some idea where to start

Can be rich both banks & driven lean

Here's a link to code P0171. P0171 OBD II Trouble Code System Too Lean Bank 1 YourMechanic Advice Here's the link to code P0174,sounds as you have a vacuum leak. P0174 OBD II Trouble Code System Too Lean Bank 2 YourMechanic Advice

possible solutions are, a dirty maf sensor. remove manifold air flow sensor and clean it with maf sensor cleaner. you can buy a can at any auto parts store to clean, take off and clean maf sensor, do not touch inside of sensor it is very fragil. when cleaning sensor be sure it is dry before installing it back on vehicle. also check for a vacuum hose leak downstream of maf sensor.make sure air filter is clean. this usually takes care of the problem. po171 and po174 are the same. you can use electrical cleaner to clean sensor also. also check for a dirty fuel filter and fuel pressure, if needbe.

Code PO171- Lean mix of Bank 1.
Code PO174- Lean mix of Bank 2.

Most of the time a P0171 and P0174 is caused by either a vacuum leak--more than likely the PCV hose and valve or a dirty or defective Mass Airflow (MAF)sensor. Low fuel pressure can also cause this condition. The PCV hose is located on bank one but can affect both sides because the other end is located on the back of the upper intake manifold. Usually they deteriorate and get a hole in it.

Clean the the MAF sensor with MAF cleaner, which you can pick up at any Auto parts store and also pick up a bottle of fuel injector cleaner. Good luck and hope this helps.

This is an indication that the PCV Elbow Hose is cracked or eroded. Also check the fuel filter.
Either of these 2 are faulty. Replace them, it will be solved.
Thank you Sir, Have a nice day.

your computer is reporting bank 1 and 2 too lean, usually caused by the mass air flow (MAF) sensor, you can usually clean this sensor and reset the light. Clean it with electric cleaner or brake cleaner, make sure it is dry before reinstalling, also take care not to damage it. Hope this helps, let me know

1. P0171-bank 1 lean, usually oxygen sensor
2. P0174-bank 2 lean, usually oxygen sensor
3. PO402-EGR ins. flow, Clean EGR exhaust tubes and replace sensor should fix this problem