I have had a code PO449 for a long time now. I replaced both the front and rear vent valves and solenoids (the one on the engine and the one on top of the gas tank). I also replaced the gas cap. The check engine light still comes on every second cycle after resetting it. I don't want to spend a fortune at the dealer but the light is bugging me. Once the light is on for this minor problem, I have no way of knowing if another problem is present until I read the code.
I have a '99 GMC Sierra 5.3 auto 4x4.
Edited by Indy, 13 April 2005 - 07:47 AM.