So I just ran my 2004 360 spider for the first time this year yesterday. The car sat in a heated garage over the winter since November. I just pumped up the tires to 43 psi and added an stabilizer additive to a 3/4 full tank of gas. Before putting it away for the winter, the check engine light was on and I just figured I would have my guy look at it in the Spring. However now after running it yesterday for a good hour or so, the check engine light never came on. I am curious your thoughts on if the fuel stabilizer additive may have helped clean the fuel injection system thus putting back to normal the gas/o2 mix? The car runs great, I never noticed a performance change when the check engine light came on.