Fuel additives is a topic that's been discussed quite a bit on here. One of the studies commonly referenced is this one:
http://www.dieselplace.com/forum/76.../177728-lubricity-additive-study-results.html
I ran PS Diesel Kleen (w/cetane boost) for a while, but then I began to run Howe's Diesel Treat (NOT the Meaner Power Kleener) for the last few months. No appreciable difference from my perspective, although when I replaced the fuel filter about a week ago I filled it with Howe's first. She REALLY seemed to like that. As for qty, when I ran PS I was running a bottle meant to treat 100 gallons and I would simply split it between the two tanks. For Howe's, I would run the smaller bottles when I could find them, but they're kinda rare around me, so I usually ended up buying the big one. Admittedly, on more than one occasion I dumped the entire big bottle between the two tanks, mainly because I'm not a fan of having half-full bottles of fluids running around the cab of my truck. WAY overkill, so it's really not fair to compare any results to the PS Diesel Kleen.
Based on some popular reviews on here, the next additive I plan to run is the Stanadyne Performance Formula. Just ordered a case of the 16oz bottles off Amazon last week. Supposed to be good stuff, and comes in smaller bottle that I can consume entirely at each fill-up.
Now, overall, have I noticed a difference running additives? Well, tough to say since I've been running something in the tank every fill-up since I bought it almost 2 years ago. But, my whole goal is to postpone things like IPs and injectors for as long as I can, and based on how strong the truck runs right now (@ 80K miles), I'd say I'm doing OK. And since I only fill the truck up MAYBE once a month (more if I have a trackday to tow the bikes to that month), a couple extra bucks every fill-up is no big deal.
Mike
