Today I figured I would give my 09 Laramie of which I have had for two weeks 89 octane over the 87 octane which I have put in the vehicle before. I don't know what octane the prior owner used. But after I filled the truck up my mil light came on any ideas why this happened?

Thanks

 

Did you get the gas cap back on securely?

 

Yes that was the first thing I checked.

 

Go to Checkers or someplace and see what the code says. My guess is the light coming on has nothing to do with the 89 gas.

 

Mike is right, go get the pooter scanned and see what the code is.
Could be somethin as simple as a sparkplug might have fould for a brief moment.
Might just be able to re-set it and be ok.