anybody know if the "STP" or "Wynns" fuel additives to clean the diesel injectors, are effective or worth using ?

Hi Jimmy, no, it is not worth the money! Simply use the recommended dosis of 2-T oil to the diesel, and your injectors stay clean and healthy.

YF

I use Millers Diesel Power Plus. It cleans the injectors, lubricates the pump and adds 2 to the Cetane number of the Diesel so improving output (for power or better economy, however you want to use it).

Shell make all sorts of claims for V-Power Diesel but however right they are, the extra price can never be recovered by improved economy so I don't use it.

Chris Gone... 2013 XS TD4 Manual Firenze Red
Gone... 2008 (09MY) XS Td4 Manual Stornaway Grey
Prior... 2003 G4 Discovery 2, 1998 Disco 1 and 1997 Disco 1 Company car before that
Also gone in Nov'13, after 7.5 yrs, to new owners with time for more TLC - 1980 Series III 88
Current 2015 Discovery Sport HSE 2.0

I tried using shell V power in my Mk1 Freelander and I was getting 40mpg on a 80 mile round trip to work and back, this included crossing a city centre. I was getting 37mpg using Tesco diesel beforehand. I never got round to working out if the cost differences.

I pop a dose of millers in every 2-3 tank fulls, just to keep things nice and shiny. 07 Freelander 2 TD4SE Tambora Flame, side steps, privacy glass, mud flaps, boot liner and a tow bar. Ok it's the Wifes but she lets me drive it occasionally - if I've been good!

Yep, I'm a Millers fan too

Adding Millers is pretty much the same as using premuim fuels such as Shell V Power or BP Ultimate. Adds up to 4 on the cetane count plus a few other chemical goodies to keep things clean. Using Millers is cheaper than buying the premium brands, just over 2p per litre if you follow the recommended dose.

And available from Halfrauds these days ...

With the properties of modern diesel fuel I would like to see what the real results of using system cleaners really is. Once you've tasted GREY you'll never go back!