What's the fix? Knock/Hesitation

[footballcoach]

'03 Lincoln LS V8.

Hesitation. Knocking when I accelerate up moderate hill so I let up on accelerator and creep up the hill. I can feel a slight miss at cruising speed.

Diagnostic trouble code: P0171 Bank 1 Fuel System Too Lean.

What do I need to do to fix this?

Thanks.

 

[joegr]

When's the last time that you replaced all of your spark plugs and all of your COPS (ignition coils)?
What octane gasoline are you using?

 

[footballcoach]

A while.
Should I start there or should I clean the MAF sensor, or all of the above?

 

[joegr]

If you can feel a slight miss, then it is most likely the coils. (You must change the plugs at the same time.) Misfiring can cause lean codes. Of course, this is a diagnosis based on very little info, so it could be something else, or it could be coils and something else. Also check for oil and/or signs of water in the plug wells.

 

[footballcoach]

I'm tied up with a funeral (wife's uncle-in-law) for the next couple of days but I'll do that the first of the week. Thanks.

 

[1LoudLS]

also if you haven't changed the fuel filter in the past couple of years, you're probably overdue

 

[footballcoach]

Thanks.

 

[Kumba]

Mine was idling rough, but more or less ran fine under load. Found the issue over the weekend, stupid mechanics couldn't get that PITA air box back together right so they just kind of half-ass'd it and called it good. Air filter was also nasty. Replaced the air filter, re-seated the air box and properly latched it, and cleaned the MAF and i'm back to decent idle and a more responsive throttle.

I never had an issue with a miss or anything, just rough idle and the engine feeling a little sluggish. Point being you might as well clean the MAF since it's easy to do and only cost you $4 in cleaner spray. Make sure you use actual MAF cleaner and not something else.

 

[footballcoach]

I changed the fuel filter (original) and it helped a little but I still have that 'miss'. I'll be busy the next few days but will try to get to the MAF sensor soon.

 

[Kumba]

It's actually easier to clean the MAF then change the air filter on these things. It's right on top of the snorkel. One connector and two T20 screws and it's out.