A few months ago I took my '06 GT to the dealership because I had an exhaust problem. I noticed that everytime I idled or punched the gas, I could smell sulfur, as if my cats were going out. The dealership told me that wasn't the case. They said it was because I was using regular octane. I switched to 93 and though not as often, I still smell it once in a while.
I also just finished reading a thread stating that S197 v6 and GTs can use 87 octane. Why did Ford tell me to upgrade my octane if it wasn't needed? Has anyone else experienced this? Any help would be appreciated. Thanks.

 

They actually told you to use higher octane fuel? Haha wow. Did you ask them to pay the difference since Ford says to use 89? Just take it to another dealership.

 

The GT's use 87 on the stock tune. Using 87 or higher does not provide any additional performance. You need a tune to take advantage of the higher octanes.

If you're smelling sulfur, try a different brand of fuel.

 

haha they told you to use a higher octane fuel...wow...I would take it to another dealer. Yes the GT and v6 can run on 87. Using a higher octane fuel wont provide any more performance then 87. You can also try using a different brand of gas.

 

what brand gasoline were you using?
Sounds like you might have got some cheap, high-sulpher Mexican gas from an independent station... Or an ARCO!
Avoid both, but no need to put premium gas in a stock Mustang.

 

Awww hell. I feel stupid. I've been using 93 BP lately, since that's what Ford "recommends" (cough)sponsor(cough). Like I said, I still smell it once in a while, but not as bad as when I was using 87 from on post at Ft. Bragg.