New to tw and need help with a p0456

I just joined two because I began modifications on my 2009 prerunner. I bought a smoke tester but have no clue where to connect it too to do so.

 

did you try just replacing the gas cap?

 

I tried 2 different oem ones

 

Do you know where I should plug in my smoke machine?

 

A very small leak (0.02in) sometimes can be very difficult to find.
You will need a scan tool to command the vent valve closed, you can hook your smoke up to the line at the purge VSV (shown below assuming you have a V6).
Also test the Purge VSV, with the engine running and the electrical connector unplugged there should be no vacuum present at the port.
There is also a TSB for p0456 if no leak is found to update the PCM to the latest calibration.

 

Thank you! I'll follow with updates