Never mind after about 62 miles the light went off by itself. And my truck passed inspection for the State of Texas. That part did help out, now I know what to do if it ever goes bad again or if I ever get the P0449 Code again. Thanks everyone.
I am getting the error code P0449 so I changed out the gas cap and the evap vent valve (acdelco part #214-2149 that i got at the motor parts in town for $20) and the light is still on. i have ran the truck for about 50 mile and it didn't reset. should i take it to see what is wrong now or should i have them reset the light???? Please help.