Granville 1428A 10K Boost Catalytic Convertor Cleaner

It works and is as good as the top branded ones I have used before at twice this price, I put the whole contents into my fuel tank I had a full tank of petrol and drove on the motorway for about 160 miles, it cleared the smell of rotten eggs and the engine seems to run much smoother now, I must say my miles per galloon is much better too I'd say an extra 4 miles on the galloon.

I had failed emissions test on mot by about 50%!!! but was fairly new exhaust system.. So i changed my spark plugs, bought this product on next day delivery put it into my car with high quality fuel in my car, drove about fifty miles at high revs (ie third gear a lot of the way) on a fast road, that seemed to clear the exhaust system and my car passed the emissions test. Not sure what made the real difference but I'm sure this stuff helped. I normally do short journeys so apparently doing that gunks up the catalytic converter, this product and the longish drive seemed to help clear the problem out.

2nd purchase, will definitely buy more!!!

Seams to have worked, engine light came on so took focus mk3 zetec s to Collins Performance to identify fault, they said it was the Catalytical converter not working properly they reset the fault but said it would probably come on again. So after a bit of research i bought this cleaner, and the light has not come on since also it seams to be a bit more responsive.

Just put in car - just wish the manufacturer had put a note on saying careful with Ford capless system. 80% of liquid never made it in, the little metal flap didn't open and the liquid went all over the floor (through the petrol overflow). Somewhat miffed, but not to be beaten have ordered another bottle and will try again, now we can get the flap open.Look at photo 1 the bottom release catch and the two upper catches at about 10 and 2 if it were a clock. All need to be pressed in for the metal flap to open. If the screw end is visible, it's not getting past the flap, should look like picture 3 when it's correctly fitted in. Would have done video but starting to rain, and need two hands to get flap out of the way.My bad I suppose, so taking it on the chin, will see what happens and will update in a few weeks. 3 stars to start, will update accordingly.

Excellent product that does everything it's meant to at a very decent price. Will be purchasing for my cars in the future.

tried this product and had no effect on cleaning the cat

No stranger to products similar to this one, I've used STP on my 2 litre petrol Mazda for years now, decided to try this after a clutch burn and change. Wow, what a difference in the actual feel of the acceleration, the pedal response seems to be so much more engaging with the driver. Exhaust fumes are cleaner now, for sure.