Originally Posted by Sidez
I don't think they payed for the gas themselves and if they did.. the difference between 91 and 87 is ******* change, I know I would never do that... but if it is true and they did do this and you have not noticed much problems as of yet.. I wouldn't worry too much, maybe check what the spark plugs look like?
Ah yes, the old spark plug read!
That is one of the oldest, and still pertinent, diagnostic tools of the trade!!