2004 Endeavor with Check Engine light on. At least second time showing PO456 code, checked gas cap. After coming back on, rechecked, now being told PO442 and recommending replacement of filler neck assembly at $500! Concerned this is not problem, and chasing. Lots of money! IMFEDUP

SOURCE: check engine light is on code#p1750

yes you should have it scanned for any other problems but also change out the solenoid.

Harvey N Tawatao

• 3854 Answers
• Posted on May 02, 2009

SOURCE: CHECK ENGINE LIGHT ON CODE P0170

DTC P0170 applies to fuel trim malfunction on all 2.4L vehicles, 3.0L Federal vehicles and right bank (bank 1) on 3.0L California vehicles. 
DTC P0173 applies to fuel trim malfunction on left bank (bank 2) on 3.0L California vehicles.
DTC Set Criteria (2.4L)
Engine is in closed loop control. Intake air temperature is more than 14°F (-10°C). Barometric pressure is more than 11 psi (76 kPa). Volume Airflow (VAF) sensor output frequency is 88 Hz or more. Code will set if long-range fuel correction is less than -12.5 percent, or more than +12.5 percent, for 5 seconds and short-range fuel correction is less than -10 percent, or more than +10 percent, for 5 seconds. 

Engine is in closed loop control. Intake air temperature is more than 14°F (-10°C). Barometric pressure is more than 11 psi (76 kPa). VAF sensor output frequency is less than 88 Hz. Code will set if long-range fuel correction is less than -12.5 percent, or more than +12.5 percent, for 5 seconds. On 2.4L code will also set if short-range fuel correction is less than -15 percent, or more than +15 percent, for 5 seconds. On 3.0L Federal code will also set if short-range fuel correction is less than -13.5 percent, or more than +13.5 percent, for 5 seconds. 

Have the O2 Sensor changed on the Right Bank, ( passenger side of the Engine, or where the # 1 cylinder is.)
Good luck and hope this helps

SOURCE: How to install a neck fuel filler for a mitsubshi

you should be able to pull the back seat up and see 2 litte hacks in the floor it should be the one on the passgern side undo it and lift up be carful of gas

SOURCE: 1993 shogun v6 3.0 wont start no spark, then next time it will

I have exactly the same problem could you let me know what you did to get over the Issue thanks, Mark.
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