2009 tacoma po code 456 gas cap replaced with oem cap...

hello i am disabled veteran thanks for the help .... my 2009 tacoma shows po code 456... gas cap replaced with oem cap from dealer 3 times ... po code 456 removed comes back after a day or so ....no longer topping off gas tank for a month now ...truck runs strong but MPG not great ? gas cap seems to loosens itself?

 

Welcome to TacomaWorld

 

PO 0456 - Small evap leak. Has the filler neck been examined carefully? If you've replaced the cap several times, the next logical point of failure would be the actual filler next; perhaps a crack, or small 'chip' out of the seating surface for the gas cap?

 

I’m not sure how to fix your problem but, Welcome to TW…Thank you for your service!

 

Welcome to tw..... if it's not the gas cap, it has to be in the filler neck.
Did you buy the truck new or used?

 

thanks ... i cannot feel any rough spots on cap seating surface ,,, how much work to replace this area if needed? if i remove code po 456 it returns in couple of days .. i tighten cap real tight ,,, is it possible cap seems to loosen itself?

 

thanks for thank you ...i bought truck used

 

You should only need to turn the OEM gas cap until it clicks one time, the stant locking gas cap needs to be turned to 3 or 4 clicks.

 

Do you have a (factory or aftermarket) tonneau cover ?

 

thanks for the welcome!!!!!!!!!!!!!

 

no bed cover now

 

You've gone through three or four caps, I doubt they're all faulty. My next step would be to remove the cap and seal the opening with heavy duty tape, and smoke the system. It's possible there's a crack in the filler next. I don't think it's a huge job to replace the filler neck if you had; you may have to drop the tank, but as long as you run it low on fuel, that's really not difficult either. I'd estimate it's a 2-3 hour/4 beer job for someone with basic tools, and limited experience.