Inconsistent EVAP leak

[Richard Kirshy]

2002 Nissan Xterra 3.3l non SC 4WD / AT

A little background motor has 85,800 miles on it, with in the last 3 months
R/R
Upper and lower intake gaskets
Injector seals
Water pump
Timing belt
Radiator and hoses
Front brake calipers and hoses, rotors and pads
Alternator and starter

Basically refreshing the motor after 12 years of service to prevent trouble

Issue I’m having is every so often I get an error on my TORQUE APP of a small EVAP leak detected ( either P0442 or P0456 )
It doesn’t occur every time I drive the truck, perhaps once a week it will show up.
Once the code is cleared it doesn’t return immediately,(days later perhaps)
I’ve check for vacuum leaks using carb cleaner on the intake manifold none appeared, replaced any vacuum lines that had any signs of age or damage.
But I still get this random error..
Engine runs perfectly, gas mileage is ~ 17.7 / gal local driving
Is it possible the gas cap?
My question is how do I track this down if it is not consistent?

Great videos and advise BTW

Topic

[college man]

Evap leaks are best found with a smoke machine. You could do visual inspection
of the evap canister and components.

http://www.justanswer.com/nissan/56im2-nissan-datsun-xterra-se-scan-2002-xterra-showed.html

[Richard Kirshy]

Did a visual, replaced anything that looked suspect and performed a smoke test also a vacuum test.
Nothing has turned up as of yet.
As I said it is not consistent.

[college man]

You could pick up an OE gas cap to rule that out.

[Author]

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