"I purchased this product from reviews posted and still with well it’s $ 40 will see if it works as claimed and check with my scanner if any adverse or success changes to car . Well it works simply does as it states car is quieter and smoother response. My car is serviced professionally and on time and fuel economy sits at 8.9 lts per 100 km. After one 10 ml additive the results were immediate on my feel. I did realtime testing thinking a placebo effect, but no after adding the responsive additive consumption went down to 8.4 lts per 100 km, hey even the original 8.9 lt per 100 km I am happy. In my opinion the product works as stated and now will do my other family member cars ."

"I must have been using this additive for 15 odd years in a 2008 ranger and also now in a 2015 4hk1 Isuzu truck, both donks have been flawless, ranger near 300,000kms now with smaller things other than engine wearing out, I'll continue to use responsive while i own diesels"

"To early as I only put it in yesterday however when you send an email enquiry and get a phone call to answer any questions that will do me. Great service which is rare these days 🤩🤩🤩🤩🤩"

"I have been using this for many years. That’s why I keep buying it."

"Prado was idling rough at 8 & 9. So put 19 to 20ml of your fuel additive into the Prado's 150 litre tanks and at approximately the 3km mark the engine started sounding a lot more smoother, and at the end of the 8k drive I let it idle for a few minutes and the engine was purring, sounding so much more smoother, and it's idling was smack on 7! So am very pleased! Absolutely brilliant additive! Huge thank you to Responsive Engineering!"

"I’m impressed how 10ml can make such a difference on diesel RAV4 from usually 5.8 down to 4,9 l/100 unbelievable and so much smoother and I’m usually very sceptical about snake oil"