you notice the difference when you put them in. but i dont think they make much differnce. i put some in before every service. it maybe just a money making scheme. maybe the good quality expensive ones like the brand forte work?
I think they work but people sometimes expect too much from them. At the end of the day there is no such thing as a mechanic in a bottle I had a AX diesel (uuuhhhhh) that failed its emissions test even with a full service and a new exhaust it still failed. I put some Redex for diesels into the tank and took it for a drive...it then passed
I think they tested a bunch of performance fuel additives on fifth gear once and turns out that all the additives they used reduced perfomance. My thinking is that they may only give you a gain in perfomance if you use them repeatedly on several tankfuls, and if you use a car with a hefty engine.
i have never used these products because i thought that the engine may become addicted to them so therefore once used you would have to use them constantly otherwise your engine may never run the same again a bit like easy start. am i wrong??
FORTE additives every time, work a treat and have got many cars through the MOT. Have found the Forte products to be the best on the market and have been using them for 20 years +
Have a look on the website http://www.forteuk.co.uk/ Their gas and fuel system cleaners work wonders on sticky injectors.