I have a 2011 Equinox 4 cylinder. It has 20,000 miles. I started having problems with after run or dieseling. I put 89 octane gas and the problem is still there. It doesn't do it all the time. Any ideas on the problem. Hasn't turn on engine light on yet....

 

Looks like someone else would be having this problem..

 

Brought it to dealer. High pressure fuel pump was bad. They changed it and changed oil no more problems..