I have a 2003 Yukon SLT 5.3L 4 wheel drive. I've gotten a evap code on my scanner and it specified large leak. I've replace the canister a while back. I got under the truck and checked all the connections from the filler to just before gas tank. it's difficult to check there without dropping the tank. I was wondering if anyone tried pressurizing the system with about 5-10 lbs of air at the gas filler ? I have ordered a cap just to rule that out.