HI. Pulled codes P0406 = EGR replacement, correct? And P0456 = small EVAP leak. How and where to find small leak. Thank you.

 

so one could be egr and other gas cap?

 

I thought a loose fuel cap has its own code?

 

So i replaced gas cap with one from dodge. Cleared codes so have to wait and see. But now the van has a slight miss or hesitation in o.d. while doing a steady 45 to 49 on a flat with no incline or decline ,just flat. What do you think? EGR or coil or fuel pump. Guess i gotta wait for a code huh. How long for a code stored, is it by a number of key starts or something else? Thank you.