1998 Ford F150 with code P0174, I can clear the code and then comes back ON

Question

It is a 1998 Ford F150 with a 4.2L engine. I clear the code and it will stay off for at least 100 miles and then comes back on. I noticed the engine skipping every now and then when it is in a pull but runs fine the rest of the time. I changed the pressure reg. , fule filter and the plugs

Answer 1

check for intake leaks, you can also clean the mass airflow sensor with a mass airflow sensor cleaner 

P0172- Fuel Injection System Too Lean Bank 2 

Possible causes

• Intake air leaks
• Faulty front heated oxygen sensor
• Ignition misfiring 
• Faulty fuel injectors 
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Faulty Mass Air Flow (MAF) sensor
• Incorrect Positive Crankcase Ventilation (PCV) hose connection

Answer 2

P0172 FORD Code - System Too Rich Bank 1
Read more: https://www.autocodes.com/p0172_ford.html