Mr. Speedy recommended BG CF5® for our 2005 Chevy Uplander that was really running rough after a long period of non-use and was getting worse. I put one can in a full tank and drove only 12 miles round trip. There was at least a 95 percent improvement in engine firing. This is the only fuel additive I have ever used that actually works. It saved me a multi-hundred dollar engine analysis and tune up. Thanks!