I have an Evap control system leak (small) any ideas what it could be from??

 

It could be as simple as a slightly loose gas cap.

If you have a locking gas cap, it could be that. Try a stock one now that gas is cheap.

The filler necks on these vehicles are known to go bad and leak. Usually that's a P0440 (large leak), at least it usually gets to that point. Really, that's probably the most likely cause. Check the hoses (there's 4 of them), clamps and pipes in the filler neck assembly first.

If you've done a fuel pump recently, it can be a pinched or damaged O-ring on the fuel pump/sender assembly. Even if you haven't done anything with it, that O-ring (GM Part # 25027014, AC-Delco G23) can harden and crack with modern fuels.

It's almost never the purge valve or the vent valve, even though lots of places will "throw parts at the problem" starting with those two pieces.

It's usually a loose or damaged hose, hose clamp or connector somewhere. Check around the charcoal cannister, too.

 

This link explains how to find and fix the problem: https://blazerforum.com/forum/diagno...plained-35144/