Had a problem with the engine bogging down when accelerating on the highway. Then check engine light came on and problem stopped. The code said evap system. Has a new gas cap from previous code so no problem there. Any ideas on what to check, clean, or replace?

 

What is the present code so you can tell what the system is complaining about.
Then you go after that issue. Forget about the last code and what you did..
Go with the latest code.
We can't crystal ball it for you.

 

sounds like you got some bad GAS!