Hi All,

I have a 2005 Ford F150 Super crew with the 5.4 L Triton. Came home tonight with a rough running engine and got a code "PO174 System too lean bank 2".

Whats wrong? Is this a fuel control problem?

Thanks in advance!

 

Just a follow up.

I took out and cleaned the mass airflow sensor and reinstalled it. The truck runs perfect.

 

Rumble is back today, now I'm getting a cyl 5 misfire, replaced the coil and plug but no better.

Any advice?

 

How many miles? Have you ever replaced the plugs? So on and So forth.

 

Good point, it has 92,000 miles on it and has been trouble free.

Still getting the PO174 code and also "cyl 5 misfire"

Just replaced the coil and plug on what I believe is the #5 cyl. (drivers side front). No change. Is the drivers side front #5?

 

I believe that you are correct on the #5 cylinder location.

Am I correct in understanding that you replaced one plug and the other 7 have 92K on them ...?

 

Yes that's correct, I just arrived in Stockholm so I was just trying to get the truck running until I got back. But I still have a misfire and the analyzer says its a misfire on #5 cyl.

 

Wow, I can not say that I would have tried that but your situation was unique.
Now for #5, I understand that the COP connector contacts are very easy to bend. You may want to give that some close inspection.

 

Thanks, I'll check that when I get back. My next stops are Mumbai, Delhi and then Vietnam so I won't be able to check anything for 15 days.

 

Talk to you next month, enjoy your trip.

 

Okay I'm back and checked everything and still have a misfire on number 5. I replaced the coil and spark-plug, no good. I just want to confirm that the number 5 cyl. is the DRIVER SIDE FRONT of the engine? Is this correct?

 

I see where you have replaced the cop and the plug on number 5 cylinder, but have you thought about a bad or fouled fuel injector? You are in Stokholm? Try running some fuel injector cleaner through the system. Let us know the results.

 

Was scratching my head last night in my garage and called my friend who is a retired engineer at the Picatinny Arsenal here in NJ last night and he said the exact same thing you did Oldguy4. Pulled the injector on #5 and tried it out of the hole and its clogged....Bingo.

It pays to talk to old guys!

Thanks!!

 

Description:

See the description for DTC P0171.

Possible Causes:

See the possible causes for DTC P0171.

Diagnostic Aids:

See the diagnostic aids for DTC P0171.

Application Key On Engine Off Key On Engine Running Continuous Memory

All — — GO to Pinpoint Test H.

P0171 - System Too Lean (Bank 1)

This is for 09-10 guessing the DTC's might still be the same?