what could be wrong if the check engin light comes on at 66k and we have not been driving with atiltitude changes?
Could be anything, have the codes read at autozone or advance. They do it for free
could just be a loose or aging fuel cap...clean the fuel cap with wd-40 around where it seals and also the top of the fuel filler tube,before replacing fuel cap disconnect the battery for 60 seconds and reconnect it and put the fuel cap back on, the check engine light should be off and your gas cap might just work now.
It could be the gas cap, but after about 2005 most manufacturers started putting in a separate light for the gas cap so I'd have the codes read to be sure
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