I give few product reviews because most of the time they don't work. So, when I purchase I pray! Well, I did not pray this time but the product worked. Wow! Therefore, I can say with all honesty...this product cleared my check engine light. Here is what I did: First, do not clear the check engine light with a scanner. If the light is showing in your dash, then OK (leave it). Next, make sure you only have around a quarter tank of gas. Now, set your Trip A meter to zero (or calculate 25 miles by adding it to your current odometer reading). Next, place the entire bottle of the product into your gas tank. Start the engine and drive around 25 miles (mine worked at 21 miles). Note: you don't have to drive right away. You can drive the 25 miles or a period of time (mine was two days). After driving for 25 miles you should see the check engine light go out. Good luck!

Update: check engine light came back.

Some back story.... my 2016 Ford Explorer XLT ended up suffering from a burned up oil pressure switch that resulted in a loss of 4qts of oil, and burning up the cylinder 6 spark plug... When the check engine light turned on and alerted me any such problem, and it was quite a noticeable misfire on #6, I was just 5 minutes from home, I pulled into my driveway and found oil spray all down the underside of the chassis and frame, I found the leak from the oil pressure switch, and began the process of correcting the issues. New switch, new oil, filter, new spark plug and coil... then I started getting other issues, ran fuel injector cleaner through it, things were good, then a few days later, P0430 popped up, started a little rough idle... checked everything, decided to give this a whirl before I end up going to extremes...

So far, so good, ran it for about 175 miles and it's running smoothly again, data showing that it appears to be back at 'normal' operation, so I'm going to clear the code and see how things go... wish me luck.

This SAVED ME from an expensive fix. Too bad no car mechanic wanted to give me the scoop! My car had been jerking at low speeds due to a clogged converter. Car shop wanted to charge me an arm and a leg to replace it and gave me no alternative solution. Found this product from YouTube vids and then read the reviews! I had nothing to lose so I put this in my gas tank when it was half a tank and drove it for an hour. My car usually jerked every time I accelerated from a stop. Eventually the more I drove it, the jerking wasn't so rough"¦ then it started to jerk every other stop. Then only one jerk every other stop"¦ then only jerked after a couple miles of driving. And now, it doesn't jerk at all and no check engine light!! Omg I'm sooooo thankful for this product! My car is also driving much better in general! It did great for my car!

The thing is, it won't fix right away"¦ the more you drive is the more it'll run through the converter and clean it so don't think it'll work after just 1 hour etc. Also if your clog is super bad, use 2 bottles. First bottle -let it be concentrated so put it in when you are at a quarter tank of gas and run it to almost empty. Then put the Second bottle in with an almost full tank of gas! This will declog for sure!

Don't waste money buying a new catalytic converter before trying this.

I had to pass the test and this one did the trick
However light was back after 3k miles.
It may not fix the problem permanently

Would think this works the best on early stages of residue in converter.
Put recommended amount in gas; no warning light for 6 weeks...working on second treatment at this time.
Warning light goes off very quickly after mixed in with fuel in tank. Time will tell if this is the fixer or the extender.....