Personally I think they are a con but to be honest with all the bio stuff they put in fuel these days they may finally have a place!
At the end of the day petrol is an awesome solvent on it's own!
fizzy I have done a full service with all filters replaced as well as the engine oil
brightspark I have put a bottle of redex in mine and the daughters car but thought I would ask of peoples experience of products
My car is a 51 plate 2.0L Scenic and sometimes is reluctant to idle after starting when it is up to temp. It does run with a good bit of throttle and then seems to clear and then idles. I was hoping the redex would maybe clear whatever the idle stepper motor is made of before taking the spanners to it!
New plugs were also fitted by the way.