2001 Lincoln LS PO147

[AmsterDutch]

OBD-II Code P0174 is defined as a OBD II P0174 Fuel System Too Lean (Bank 2)

P0174 Symptoms

• Check Engine Light will illuminate
• In some cases, no adverse conditions may be noticed by the driver
• In other cases, there may be performance problems, such as a lack of power on acceleration and some "coughing" or misfiring
  
• The vehicle may have trouble idling, especially when warm or when sitting at a stoplight

Common Problems That Trigger the P0174 Code

• PCM software needs to be updated
  
• Vacuum leaks (Intake Manifold Gaskets, vacuum hoses, PCV hoses, etc.)
  
• Mass Airflow Sensor (MAF)
• Plugged Fuel Filter or weak Fuel Pump
• Plugged or dirty Fuel Injectors

So with that being said on the Lincoln LS where would be the best place to start? Plugs and COP’s or MAF sensor? Or both right away? Just picked her up for cheap as always wqneeds new T-Stat housing De-gas bottle/Reservoir and yes the dreaded alternator...my last 2001 had the greatest engine and only threw me one code when the transmission over-Drive went to crap
As always Thanks in advance

 

[rgorke]

Been through this...

Places to start....

Can you see the fuel trims? If they are high at idle and fine when driving, most likely it could be a vacuum leak. Can you smoke test it?

Replacing all the rubber vacuum hoses and the little hard ones that break easily.

Replace fuel filter

I fight this when it gets cold at first start up.

 

[AmsterDutch]

Been through this...

Places to start....

Can you see the fuel trims? If they are high at idle and fine when driving, most likely it could be a vacuum leak. Can you smoke test it?

Replacing all the rubber vacuum hoses and the little hard ones that break easily.

Replace fuel filter

I fight this when it gets cold at first start up.

Sounds good will be replacing all the hoses this weekend ...and yes a fuel filter is top on the list as well...thanks for input

 

[rgorke]

Anytime...but all that being said, I still have lean codes pop up during the colder winter months. They started again last week. After the car warms up and 20-30 mins of driving, there isn’t a problem.

So, what going on that causes a lean situation (vacuum leak?) that goes away after 20-30 mins of driving?

 

[AmsterDutch]

Anytime...but all that being said, I still have lean codes pop up during the colder winter months. They started again last week. After the car warms up and 20-30 mins of driving, there isn’t a problem.

So, what going on that causes a lean situation (vacuum leak?) that goes away after 20-30 mins of driving?

Expansion of rubber hose maybe ...as rubber/plastic heats up it expands but don’t know really... just a commonsensical guess...science is fascinating lol

 

[rgorke]

Expansion of rubber hose maybe ...as rubber/plastic heats up it expands but don’t know really... just a commonsensical guess...science is fascinating lol

I think I may have found the issue. This morning on first start up, I pulled out my propane bottle and pointed it around all the vacuum areas. I monitored my STFT and LTFT as I moved it around. I put it right up next to the intake manifold on the drivers side by the fire wall. After a few seconds, the STFT went from +25 down to - 10 - 15.

So, it appears I have a slight vacuum leak back there at the intake manifold. I was pointing it right where the plastic part meets the metal part of the manifold.

At least now I have some idea of where the problem is. Now, it is getting those small gaskets!!!