I don't know about you, but sometimes I have to get hit with a ton of evidence to alter my opinion. Especially when it comes to my opinion of a category of product not known for its adherence to truth in advertising. I'm talking about the fuel and oil additive product category.

Recently the folks at STP, to get my and my fellow editors' attention, brought us all out to California Speedway in Fontana, California, to participate in the Richard Petty Experience. I thought, sure, I'll take a few hot laps in King Richard's cars and listen to the pitch on STP's new line of fuel additive products.

To my surprise, the marketing and research and development people didn't present a branding strategy based on the image/perception of the container by the target market. Instead, they laid out the science behind their products supported with, as far as I could tell, reputable statistical studies and before-and-after data from test engines.

The most impressive was a before-and- after bore-o-scope look at the valves of a one-cylinder test engine after it had run the equivalent of . . . I forget the exact figure, but it wasn't a high-mileage figure, say around 20,000 miles. The fuel deposit buildup in the port and on the valves was substantially more than I expected to see. The deposits collected on the valve's back and around the stem to a depth of around 1/2 inch. Yet after treatment with the Complete Fuel System Cleaner, the deposit thickness was reduced significantly. It wasn't perfectly clean but reduced in a way you could tell that the additive came from the injector.

Norman Berke, the R&D guy, says such deposits aren't as rare as we might think, and that they can become thick enough that they actually absorb enough fuel to cause temporary lean conditions. Lean enough to cause misfiring and to confuse the engine management computer and cause loss of performance and mileage as well increasing the waste stream of the engine.

But Why The Deposits In The First Place?
The reason fuel deposits are more of a problem today is that the Environmental Protection Agency (EPA) has allowed the additive performance standards to fall by half. This goes back more than 20 years, since about the 1980s, when fuel deposits became a concern of the automakers, most notably when BMW disclosed publicly that its engine's performances was being negative impacted by fuel deposits.

At any rate, fuel quality is a concern for top-tier carmakers. They're unhappy with current fuel quality standards because it is a quality-perception problem with their customers. Let's face it, when your $40K pickup is idling rough and coughing at 60K miles, you're not going to be happy. And you're not typically going to be blaming the economy-brand gas you've been fueling with, either. In an effort to keep customers aware of where these "quality issues" originate, most automakers have established "top tier" gasoline standards. These recommended gasoline brands and grades have more of the good stuff to keep your machine running smooth, powerful, and clean.

OK, so the factories see fuel-deposit-induced performance loss as a legit problem and higher quality fuel with appropriate additives as the solution. So what's that got to do with STP's fuel additives beyond the fact that they bought lunch and the laps? As I said, I'm really a skeptic regarding chemical additives. But I'm also open to new information, which, as it turned out, I was provided with from an unexpected source.

Not two days after getting STP's pitch at the California Speedway, a friend of mine bought a used '00 Dodge Ram. He got a good deal and was very happy with his truck when he dropped by to show it off. Of course, we had to road-test it, and he put me behind the wheel. I hate to be the bearer of bad news, but after driving his truck, I noticed right away that the idle was rough, but far worse was that it had a flat spot and it misfired and popped up through the intake when you squeezed on the throttle at freeway speeds.

The symptoms were unmistakable: lean misfire when the driver tipped in the throttle. The only question I had was why? It must be a sensor failure I thought at first, but then again, these symptoms were what the STP crew claimed that fuel deposits caused. Now I just got a new gift bag of STP additives to test, so why not? As my friend was going through as serious bout of buyer's remorse about this time, I whipped out the silver bottle of STP Complete Fuel System Cleaner and we drained it into his newly filled gas tank, telling him that before he takes it back to the dealer to fix it, try this. Who knows, it may work?

Cutting to the chase, the product worked as advertised. About half of the way through the tank, the idle smoothed out, it started easily, and the lean misfire at throttle tip-in vanished. So, much to my surprise, my pal's truck is running well and getting better gas mileage.

The moral of the story is that even in a product category that seems sometimes to be lumped in with faith-healing mechanics, there are reputable companies making effective products. STP is one of them, and I'll be sure to add at least the fuel additives to my summer driving season tuneup and maintenance regime. I'm also going to be more aware of the quality of gasoline I'm using. Hey, I'm now a firm believer in better driving through chemistry.