Off-Topic Help Needed! (Kind of Long)

[Terry Peerson]

The wife's car is a '96 Tahoe with a 5.7-litre, vortec V-8. It has started "pinging" when we're pulling a hill. Actually, the "pinging" started about a year ago. At that time, I started using mid-grade gas. That seemed to take care of it...for a while. Then it started again. So, I changed to Premium fuel. Again, the pinging stopped. Now, I am using the 92-Octane premium gas from AMOCO. But, the pinging has started again. The car only has 70,000 miles on it. And, except for the detonation seems to run like a scalded dog. Idles smooth. I am thinking that I must have a carbon problem. I know that I saw a post on here that recommended some kind of fuel treatment that really works to remove carbon deposits. Any reccommendations?

Sorry this is so long,

Terry