2023 Lincoln Navigator — fuel trims are positive at idle and improve with RPM

Log the conditions before you spend. Get a real battery/charging test on the 2023 Lincoln Navigator, not just resting voltage, before blaming a module. That's the branch I'd chase this week. On “fuel trims are positive at idle and,” that was the fork that mattered for me. I'd want a dollar figure or a measured spec, not 'should be fine.' I'm in no rush to be a hero on it.

Start with the test that can prove you wrong. Get a real battery/charging test on the 2023 Lincoln Navigator, not just resting voltage, before blaming a module. Don't erase codes until someone who can help has seen them. I'd want a dollar figure or a measured spec, not 'should be fine.' Worth doing even if the car feels fine right now. I refuse to clear codes until someone else sees them.

I'd want a measurement, not a hunch. Swap the cheap/easy piece first on the 2023 Lincoln Navigator and see if the fault moves. Save the big job until that test fails. Had a similar mess a couple years ago and that's what finally sorted it. Might be overthinking it, but I'd rather overthink than overspend.

This is usually cheaper to test than to guess. Write temp, speed, and in-gear vs coast when the 2023 Lincoln Navigator does it — then decide on parts. That's the branch I'd chase this week. If it doesn't change the out-the-door or the repair estimate, it's noise. Might be overthinking it, but I'd rather overthink than overspend.