I recently purchased a 2007 s60 2.5t and I know it takes 89 or up gas (that's what it says in the service manual) and every time I've put in gas the check engine light comes on and it starts to idle funny. If you can help me out I'd greatly appreciate it. I love this car and I want if to run top notch

 

You can run 87 with no problems. You need to have the codes read to have any idea what is going on.