I first used FTC pellets in my 1999, Renault Megane Scenic with 180,000 miles on the clock. because the car nearly failed the MOT emissions test. Having added the pellets there were quite a few clouds of smoke to start with, but, after about 50 miles or so this began to lessen. I had been averaging 33mpg, which I thought was pretty good for an old automatic, but during the first 500 miles this changed to almost 40mpg, where it has remained. As an added bonus the engine is much smoother and more lively. I have just added the pellets to my recently acquired 1989 Talbot Express camper van. Thank you for supplying such an effective product.