My mother's car with 100,000 miles on it is starting to ping on the factory recommended 87 octane but runs fine on 92 octane. I suspect carbon build up in the combustion chamber. What's the best way to remove carbon? Is there an additive or something for this, or do the heads need to be removed? I'd hate for her to keep buying 92 octane unless there is no other choice.

Thanks,

Jim

Jim,
How about some details on the vehicle and engine ?

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Bill Koustenis
Advanced Automotive Machine
Waldorf Md

1971 Heavy Chevy - original owner
Team Chevelle #100

Bill, It's a '95 Ford Taurus. I'm not sure about the cid but it's a V-6.

Thanks,

Jim

Jim,
I did a search on a couple of databases I have access to and found quite a few mentions of egr problems causing detonation on the Ford 3.8 V-6's. I am pretty sure that is what you have. One of the most basic reasons for egr is to suppress detonation. You might want to try activating the egr valve with a hand held vacuum pump to see if it affects the idle at all. If it does not, the egr valve or the passages in the intake and heads might be clogged up. Might save some bucks by finding a good Ford shop and have them check it out.
Hope this helps,

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Bill Koustenis
Advanced Automotive Machine
Waldorf Md

1971 Heavy Chevy - original owner
Team Chevelle #100

Thanks Bill, I don't have a vacuum pump handy, but if the valve isn't too expensive, I might just go ahead and change it. Once I have the valve off, hopefully I will be able to see if I have clogged passages.

Jim

Jim,
Depending on its location and construction, a lot of itmes you can reach in and actually operate the egr valve by hand. Be careful as it can get hot, but I have done it as a test on GM cars before.

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Bill Koustenis
Advanced Automotive Machine
Waldorf Md

1971 Heavy Chevy - original owner
Team Chevelle #100