I have a 2003 Chevy suburban and the check engine lights keep coming on also a reduced engine power light. I took it to a mechanic, nothing!
You might try taking it to a parts store that offers free diagnostic readings. The newer cars have a plug-in that reads out a code of what's wrong and you can work on getting it fixed.
Ride her till she bucks you off !!!
Try taking it to Auto Zone.
Maybe higher grade fuel???
Have the code read