I have used fuel additives on and off since I got my first diesel in Sept' of 2002 but when all the talk about injector failures began I decided to be religious about using it. Up until now I've been using either the Power Service Diesel Kleen or the regular Power Service in the white bottle. Although, since I started using an additive with every tank of fuel I've been using the Diesel Kleen exclusively. I will say I've noticed a positive difference in my truck's performance, it's quieter and runs smoother. However, this effect took about 5-6 tankfuls but has remained constant since.
Additionally, I have been doing a lot of reading over on the Dieselplace regarding different types of additives. There is a ton of discussion regarding whether to use additives that either Demulsify or Emulsify the water in the fuel. Like the oil wars, these guys stand behind whatever additive they use.
Demulsifier additives make the water molecules attract which causes water droplets to form and drop to the bottom of our fuel tanks. Thus the water remains out of our fuel system and high pressure injection pumps.
Emulsifier additives keep the water molecules seperated and thus they pass through the fuel sytstem. Unfortunetly our high pressure pumps and injectors do not like water.
GM supports the use of Demulsifying additives for the D-Max which uses a high pressure pump like we have. This also may be why DC does not recommend using an additive because if you use an emulsifying additive you can cause damage.
After doing a lot of reading I have decided to switch over to Stanadyne fuel condtioner. It is hard to come by but seems to be a better product than the Power Service. I ordered it here
http://www.scheiddiesel.com/stanadyne.htm and they have a special running until the end of the month. I got the "One Shot" bottles so I don't have to smell the opened bottles of PS any more.
I have learned quite a bit about additives in the past month or so. I suggest you guys do some reading over on the
http://dieselplace.com/forum/default.asp and search for "fuel additives" or "demulsify" or "Emulsify". These guys have been dealing with injector problems for awhile and they have researched fuel additives extensively.
Good Luck.