Over-Ripe Mystique

courtesy of Bob, The Auto Answer Man

I have a 1997 Mercury Mystique with 44,000 miles on it. Currently, it is emitting a sulfur-like smell from the exhaust. I have read several letter on your web site pertaining to this issue. From these letters and my own automotive knowledge, I presume it is being derived from the catalytic converter.

I would like to learn more about your advice pertaining to using a higher-grade fuel and using an additive. What type of additive do you suggest? I am sure you can't give any specific name's, but what about ingredients? I do not have my owners manual, because I bought this care used. Do you know or could suggest the correct fuel octane that I could use? Is this a permanent solution or a quick fix? Can anything happen to my engine if I try this solution, it temporarily fixes the problem, then the smell comes back?

And my final question is, if I take it to a Ford/Mercury dealer service dept., how will they know that the problem is the cat. converter and not the O2 sensor or something else? I ask that question, because car 1995 or newer have a 8 year / 80,000 mile warranty on major emission parts, including the catalytic converter.

The problem is in the cats, but not specifically with the cats. Using bad gas (which generally has a high amount of sulfur) leaves deposits on the cats. Eventually, there is enough to start emitting this foul smell.

To get rid of it, you could replace the cats or burn it off. Simply use a well know major brand of gas, add a fuel injector cleaner, and go for a nice long drive down the freeway. In some places, this is also known as a Tennessee tune up. Eventually, this build up will start closing down the pores inside the cat and your engine performance will start to degrade.

Not only is this a quick fix, it is cheap, and you can do it more than once, and it is actually good for the car. In addition to this cleaning phase, you need to change where you buy your gas. One tank of a bad gas could cause this to happen.
Good Luck!
Drive Safely!
Bob, The Auto Answer Man

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