Check engine light due to gas cap

EVAP is one of those systems where you could literally fire the parts-cannon at it all day long, and blow through a lot of money.

Rather than go that route, check if your local auto parts chain store has a smoke machine they'll rent (if you don't have one). Smoke test the front half using the green diagnostic/smoke port on the line above the driver intake manifold in the engine bay. If you don't clearly see the smoke leak anywhere in there, then rig something up to smoke test the tank.

Our trucks are hitting that 80-24 year age range. Rubber deteriorates. A ton of people have had EVAP issues because the rubber hoses all around to/from the EVAP canister are cracked at the ends, in the middle, or they're just loose from shrinkage. It's unfortunately nobody (I'm aware of) makes a rubber hose replacement kit for these trucks. I'm sure people would snatch them up for proactive maintenance if it existed.

 

I actually didn't need to check the code. I was putting gas in it and noticed a lot of fuel running out from the bottom of the truck, I wasn't the favorite customer of the day...
Got it home and starting digging around and found it (and found my tail lights weren't working. Had chewed wires as well I had to fix).

 

I bought a smoke machine off Amazon but I haven't used it yet. It was $80 so it didn't break the bank.

I've have to find a fitting for the evap test port that's under the hood. I bought a cheap Dorman gas cap and modified it to take a hose from the smoke machine.

My main concern has been to pass inspection, which it did yesterday. My wife's car is in the shop for brake line repair. The car is way too low to the ground to get under it for these repairs. If all goes my way, I'll be putting in a lift this winter. Tired of paying garages to do work I can do.