I usually use a fuel injector cleaner every couple of months, but I hadn't used one for a while. I'd been noticing that my fuel economy was about 25-26mpg at a steady 80mph (which seems low.) So I decided to add the Gumout this time (as I had it sitting around).

My car now has about 140k miles on it so you would assume the engine is starting to get tired... after filling up with a fresh tank of premium with the Gumout, I immediately noticed an increase in power and smoothness! The engine felt so much "looser", it felt like as if all the horse power was free (I have an EAT chip, a K&N air filter, and use synthetic oil). Needless to say when I took it on the highway I was now getting 30-31mpg at a steady 80mph!

I guess it just goes to show that you need to clean your engine internals to get the best from these engines, but to get a 4mpg increase is very cool. My OBC was showing a range of over 500 miles, which I hadn't seen for a while.

I've now decided to add fuel injector cleaner every other fill-up, as the mileage increase is worth the extra expense.