Bruce Brodie
Member
A mate put me onto an Australian Made fuel additive for diesel and petrol called DXP, the dose rate is 1 ml to every two litres of fuel added to the tank, I accidentally double dosed, didn't read the instructions, but my economy has gone up and my 550 is running smoother, I've noticed that I don't need to push down on the accelerator as much, seems to pull up hills better, a 250 ML costs $21.20, there's also 500 ML etc, but definately worth a try, just a suggestion if you want to try it. Google DXP Fuel Additive there are not that many outlets but you can order direct online.