Quote Originally Posted by Mark Rinker View Post
My conclusion (based on lots of miles, and lots of different additives tested) is that if you are looking for increased mileage / fuel savings to justify the expense - save your money.
On re-read, I failed to make the point originally intended...that is, adding fuel injector cleaner to each tankful is unlikely to provide a sufficient increase in mileage for that tankful, to cover the cost of the additive. However - adding cleaner over time is likely to keep injectors spraying freely, and avoid situations where mileage is negatively impacted, or lifespan of injectors shortened.

Bottom line - I am a believer in (quality) fuel treatments, but its very hard to measure your ROI in a repeatable or meaningful manner.