If you chip your car, is it normal to see a decrease in fuel economy ???
I would have thought no, because the engine is set to run more efficently on good quality fuel.
I ask, because I found that using Optimax, my fuel consumption suffers (by about 4-5mpg), yet if I run Texaco Super, my fuel economy is better, almost as good as before the car was chipped.
Suppose I've just answered my own question.....Duhhh