Pinto Car Club of America

Does anyone else notice a difference in performance between brands of gasoline? 

My car (a 79 Pinto SW) doesn't seem to like some brands of gas.  I put in a tank of gas (super unleaded) recently that's 10 per cent ethanol, and the car ran rough until I started putting in a more expensive brand of super unleaded gas.

Coincidence?

I drive a gas truck in St Louis MO. I can tell you this much. It all comes from the same place. When I load Citgo it comes out of  a ConocoPhillips pipeline. Another Phillips dealer loads gas out of BP. Like I said it all comes from the same place. Most of the big oil companies around here have exchanges, meaning they all help each other out.Quiktrip is big here but they get their gas from about 5 different places, whoever has the best price. The additives are what make the difference, some put more in than others but it is a law that all gas must have a detergent additive. Run whatever is cheapest and doesn't make your car knock. As far as ethanol goes, it is added to gas to increase the octane, in St Louis city and county as well as a couple of other counties in the vicinity they can only sell reformulated gas (RFG) it has ethanol to make it burn different and to give it some octane. If you go out of the metropoltan area you can get conventional gas that doesn't have ethanol. They also change the blend in May and September for winter and summer gas. You may have noticed your car runs different at different times of the year. I am no expert on the subject but this is just what I have picked up from my time hauling gas.

Hey, thanks Tercin, for the input.  I did some internet searching on the subject last night, and apparently there's a similar set-up in WA state -- five refineries supply the eight or ten or so gas brands.

I'm steering clear of ethanol for a while, until I figure out if it was a) the ethanol, b) the brand of gas, or c) the STP additive I put in to 'clean' the carburetor, maybe it made the difference instead of the more expensive gas.