Modern Vespa

I have a 06 gts 250 with 5000 miles on it. At about 4300 miles on it I filled up with 87 oct and burned half of it out before I relized it. I syphoned out the 87 and continued to run 93. Every since I did that the motor has a rattling sound in it, and the check engine light is on. There is no "rattle" at idle or top speeds, only around 20-35mph do I hear anything. Everything seems to be running fine but that noise worries me. The vespa shop is quite a hike for a diagnostic. Anyone have any insight on what the prob is or things to check? Thanks.

It is highly unlikely that the rattling sound has anything to do with your earlier use of 87 octane gas. There are several things that can cause a rattling sound; A bad voltqge regulator, worn rollers, an accumulation of dust on the clutch, etc............so if you're not mechanically inclined, take it to a dealer and get the problem solved. Good luck!