Cadillac CTS 2007 idling rough

CTS7

2007 Cadillac CTS is idling really rough. Also vibrates when still and foot on break. Just replaced timing chain 2 days ago, and was doing great. Suddenly, started idling very rough, and even backfired once. Drives great once up to speed. Anyone have any ideas? Thank you in advance.

Mr_Shiftright

You'll need a professional scan tool on there to see if you have misfires or an air/fuel mixture problem. Did you extract any codes at least with a code reader? Any chain noise you can hear? I suppose if your tensioner let loose that might cause these symptoms.