Got my new scan tool today, Auto link Autel AL619. Tried it on both my trucks, works much better (gives much more data) on my '05 F350, of course its the one thats working correctly.

On my '01 F150 4.6L I got two codes. Had a P0171 initially, cleared codes drove for about five miles, had two pending codes. P0401-insufficent EGR flow detected. Had P0171 come up again it has been the re-occuring code.
Freeze frame data shows:
Calcu. load 51%
Temp 192 degrees
STFT B-1 10.9%
LTFT B-1 25%
STFT B-2 0.0%
LTFT B-2 -9.4%
RPM 1019
VSS 4mph

Preformed on board monitor tests. Haven't a clue how to read the results.
Rear to front switch ratio bank 1-fail
NOT10 front switch ratio bank 2-fail
test $2A Data -fail
Vapour generation Max absolute pressure-fail
Delta pressure for low flow test-fail
Commanded EGR dutycycle for low flow-fail
Total engine misfire rate & type B thr- fail 12%
Cylinder events tested -fail
Voltage amplitude Bank 1 S 1 -fail, Bank 2 S 1- fail

Engine rpm drops back to around 700rpm then fluctuates between 670-730.
Timing advance for #1 cyl seems to fluctuate a lot 17-38 degrees. My V10 only moves between 16-18degrees.

If anyone can give me some insight it would be apreciated.

 

Hello,

Look at your fuel trims for bank 1.
STFT= 10.9%.
LTFT = 25%.
This is what triggered the 171 code.
The trims are too far out of limits.
.
Short term fuel trim is the more immediate table value that is set by what the Ox sensor detects and adjust the fuel injection rate by causing a change in injector pulse widths for fuel amount control.
.
The long term trim table has it's average value adjusted by the inputs from the short term values on an averaged basis.
This secondary table (LTFT) is what triggers the code.
.
The tables were given limit ranges to work over so fuel corrections can be made for engine wear, temperature changes, humidity changes, air pressure changes and differences in fuel quality, over time.
If the tables were not given any flexibility to change control of the fuel, the vehicle would be in code nearly all the time for every little difference the OX sensor were to detect.
A 25% limit put on this table is enough. 10% would not be enough as you see by the readings.
.
Now, with your Scanner, do some spraying for the air leak and watch the Scanner live STFTs for a reaction as it's in full time/real time monitoring and will react immediately when the leak area takes in the spray and is the reason you can't hear or see a change by just listening.
Good luck..

 

Thanks Bluegrass, figured you'd chime in. Since I always only get the 171 code for bank one lean only is it fair to assume its not a vacuum line and most likely an intake gasket?
I've got a set of gaskets here as well as a pvc filter and am waiting on a complete set of coils.
I know look at fuel trims and spray. What do the readings for sensor two fuel trims mean they are both at 99.2%

 

Would this cause it to run rough, hesitate and have a lack of power. Its showing no misfires.

 

You may have more than one cause and effect.
Clear the air leakage first then let it normalize then see what you have left and address them one at a time or you get confused thinking it's only one issue for all the things you see..
Good luck.

 

I tried spraying the intake and along the cylinders on bank one. Didn 't notice a difference in STFTs they seem to bounce around alot anyways. They never showed a negative value. Between 0.3 and around 9.5 The other bank bank two showed between -3 and 3 but usually hovered around zero. I tried it several times used a whole can of brake clean. The first two cans of brake clean I picked up in the shed were non-flammable, didn't realize they made it, had to go to my buddy's and get some flammable stuff.
Bank 1 never settled out. Even while not spraying it bounced a lot.
While in live data I put it in gear and reved it up while holding the brake to put a load on it. The only time I saw a negative value on bank one was when I took my foot of of the throttle fast and the STFT dropped to -23. Then went back up to a positive number.

 

As a side note. Truck seems to idle very well. Idles pretty smooth. Not till you apply some throttle that you really notice the hesitation, stumble. You really notice the hesitation, hitching, bucking when in gear at 1500 rpm or less under load. As soon as you let off the throttle it smoothes out.

 

I cann't seem to find the air leak. Are there any suspect places I should look? Spraying all around and under the intake showed no different response than not spraying. Do these engines have a culprit similair to the 3.8/4.2 v6s isolator bolts ? I can hear a noise when I rapidly open the throttle, like when you have your air intake tube off and open the throttle you hear the engine take a gulp of air, it sounds to be coming from down under the intake maybe? Its not coming from the intake hose seems to be coming from somewhere after the throttle body. Sound just like the air leak in a guys 3.8 windstar I listened to the other day.