Toyota Repair: Check Engine - code problems, technical information systems, service bulletins

Question
2003 Toyota Tacoma Truck 2.4 liter stick shift with 110,000 miles.  I have code P0451 and P0466 listed as Evap Emission Control: vent malfunction and pressure sensor range.  I was going to replace parts but was told this is an OEM part.  If I just replace the parts might the problem be resolved or would you suggest having a dealer do the work?  I notice I have a hard time filling the gas tank since the engine light came on.

Answer
The evap system is complicated and not exactly easy to diagnose, it takes somone that really knows how to proceed with troubleshooting, there are a few tests that need to be done to determine the cause, I have checked toyota's technical information systems to see if there are any service bulletins that apply to these codes and there are none. I would recommend having the toyota dealer check this, one reason is that depending on what part has failed it may still be covered under the emission control warranty.