Fuel trims?

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Feb 21, 2019
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Denver, CO
Hi all,
(2013 F150 3.5 )

I have some oddities with fuel trims. While idling my STFT stay close to 1.00. When I hit the AC they can climb up to 1.20 but then slowly settle down. My LTFT is usually around .93-.96 while idling. When I am cruising it gets higher to around .95-.98 but when I start hitting boost they both are around 1.00.

Would this indicate a vac leak? While idling I am about at 17-20 in/hg (Mind my elevation: 5200+/-) My AFR (lambda) is around 1.00 while idling sometimes jumps up to 1.05.

Is this acceptable or do I need to grab more info?

Thanks for everyone's thoughts!

(Just cleaned all MAP sensors)
 
I think within 2-3% is ideal, up to 8% is ok, and when you exceed 10% approaching 20% that is when there is a problem.
It sounds like you are between ok and ideal...I don't see any issue.

Also, less than 1 indicates you are running rich, so would not be an indication of an air leak.
 
ah ok so I had it backwards.

Thank you for the confirmation. That is what I was thinking but just wanted to make sure! I am talking to the tuner as well and he is saying the same thing as you.
 
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