Wynn's Extreme Petrol System Cleaner - Complete Fuel System Cleaner - 325ml

I’ve been using this regularly for a few years now, about every three months. It’s very easy to use — just pour it in with a full tank. I notice smoother performance and slightly quieter engine noise afterwards. Not sure how well it would deal with a serious build-up on parts like the lambda sensor, but for regular use it seems to protect the system well. It gives peace of mind and keeps things running clean. Good value for money and as effective as any other product I’ve tried. I use it in a Toyota hybrid — the dealer says it doesn’t make much difference, but with the varied petrol quality around, it feels worth using regularly.

Why did you choose this product over others?: I bought this for my aging but trusty Mercedes B class. The man reason that the engine was rough idling. I poured the hole bottle in and added £40 unleaded. After 2 days (45 miles) the problem was gone! Also I have had an engine light on for a year that my mechanic said was the fuel emission's sensor, that also vanished. Also the car seems to respond better now and starts with the feel of a new battery. So (so fingers crossed) I’m amazed ! This little bottle seems to have saved allot of cash down the garage. My mechanic suggested using this before changing filters, plugs, fuel pump, sensors etc. I’m going to use it every two months from now. Best purchase for years!!

I use this maybe 3-4 times a year as my car will easily do 15k miles in that period, and as it has north of 150k miles on the clock now, I want to keep the internals as clean and healthy as possible, coupled with regular servicing and maintenance of course. I've found this particular additive to be the best, and also use the diesel version in my 2nd car. What's noticeable is the car drives smoother, idles better, acceleration is improved and along with that economy is noticeably better. For reference my car is a performance hatchback, 2.3L turbo petrol, and for a car that is now nearly 14 years old it feels like a new car and is very responsive. Again, regular servicing and oil changes help that, but I'm a strong advocate of using this product to keep your injectors and other internals free of soot and whatever other deposits clog them up.

Good product for use added to fuel

Been using it for a while now good product

The car seems to be a little smoother on acceleration since using this. It could be my imagination, but I think it's made a difference.

Worked well on my daughters Corsa gets more MPH now

No immediate effect