2007 Tahoe code P0455

Any good way for me to do the smoke test or is this a dealer thing. What do you think about the fuel tank pressure sensor?

It needs to go to A repair shop, not necessarily the dealer for testing and repair!!! Smoke machine and a professional scanner needed for ACCURATE test!

One last thing....I also notice that when I pump gas, it stops numerous times making it hard to fill the tank. Any indicator of how that is related?

My symptoms are exactly the same. CEL came on, showed p0449 & p0455. Pump shuts off several times trying to fill up. I replaced the vent valve solenoid & reset CEL. Light didn't immediately come back on. About the time the tank got about halfway empty it came back on. Had codes read and this time it's only the p0455 code. I have not yet replaced the gas cap or had it smoke tested since it's not a cheap test. Did you ever figure out the problem on yours?

I did. But first, I ended up replacing the gas cap. No luck. then I replaced the Evap canister that sits under the truck above the transmission area. No luck. I finally took it in. It was the Purge Valve that is in the engine by the manifold.