I have got this reading on my instrument panel a few times and a check engine light. I have tightened the cap and it did it again. Should I just go buy another cap?

 

That would be a wise start. Your cap may not be sealing properly any more but if a new cap doesnt solve your problem you may have a faulty vent solenoid or leaking evap hose.

 

Check the connection behind the driver side head of the evap line. Its where the hard plastic line disconnects from the line that goes back towards the tank, mine was clipped, but apparently didn't clip all the way and gave me the same code. Obviously a bad gas cap etc... is possible.

 

I have gotton the 'tighten gas cap' a few times,new cap worked for a while but still get a random one.

 

Oh I will check that stuff. Thanks