Shoutout to the old timer in Dayton who talked me out of a $900 parts cannon
I was dead set on swapping the whole fuel assembly on a 2004 Silverado with a P0171 code, but he told me to smoke test the intake first, and it turned out to be a $12 vacuum elbow behind the manifold. That was 3 weeks ago and the truck has not thrown a code since. What is your go-to cheap test before you start throwing parts at a lean code?