My car has 2 catalytic converters that need to be replaced. I live in NW Indiana and we have to get our cars emission tested every other year and unfortunately this is the year it had to be done. The check engine light was staying on and a vehicle will not pass with the light on. I used this product several days before trying to test emissions. The light came off almost immediately and it passed the test!! Now I have two years to decide what I want to do with the car.

Seems to have cleaned bank.1 on my 2008 Ford Escape.to where the input signal no longer longer matches output but output isn't a flat line which is desired. I am going to do a tuneup first and then try a second bottle in case the spark plugs are part of the cause for tha cat going bad. I am hoping the P0420 light stays off now even though the cat still isn't working perfectly it is much better. I would say if you are getting a P0420 light every 100 miles or so this may fix your issue because chances are cat is just dirty and not broken but if you light is always on it may be a waste of your money because the cat is probably broken. I am guessing that's why it hasn't done anything for some because they let it go too long. I bought this car a few months ago and found out the cat was clogged later. If the light doesn't come back on I will be a happy camper because the car runs great otherwise. I will update this post later after the tuneup and second bottle of cleaner. If the light stays off I will change the rating to a 5.

It really worked! My engine light came on, had gone to automotive store which they indicated my catalytic converter was going out. I of course like everyone else can't afford thousands of dollars to buy or rebuild a transmission. I try to start from the smallest issue glad that I did for under $20 it was worth it. Also on the instructions states to use this item every three to four months. I'd rather get this as required than buying thousands of dollars on a transmission in the long run. *Be sure to buy Cataclean when your engine light comes on and knowing it's your catalytic converter*.

After reading several reviews of this product, I decided to give it a go. It work exactly as advertised. My 2001 Chevy Tahoe kept kicking out a code for catalytic converter problems. I followed the instructions exactly as it was on the bottle and the code has never come back. As some of the reviews for had stated and the bottle also states it is a good idea run a second treatment through. After running the second treatment the vehicle is running very smooth and I definitely have seen an increase in the gas mileage. I have a high mileage Tahoe with over 235,000 miles. I believe some of the reviews where people fit the product in the work they may have had more difficulties with their catalytic converter system to just being dirty. Obviously not all power to work all the time for every application but I believe in this product.

I had a check engine light on, which was a pretty significant bummer since I had to get an emissions test to renew my registration; in my state, a check engine light is an auto-fail on emissions tests. Bought an OBD meter (also a great investment), said it was a catalytic converter issue - I cleared the code multiple times, but it kept coming back. At the prospect of a $700+ repair/replacement, I decided to try Cataclean instead.

I did it mostly by the instructions, but also incorporated the recommendation of a commenter (may have been on a different website)
- I put it in right before I got on the highway. It was about 9 pm, so it was mostly empty.
- I got into the left lane, and continuously revved the engine to the highest RPM's I could, then let it settle down. Did that for about 20 miles.
- When I got home, I used my OBD meter to clear my codes. Drove for about 50 miles before I went in to get the emissions test, passed with flying colors.

I've driven 500+ miles since, code has not come back. Definitely recommend this for anyone who knows the engine is throwing a catalytic converter code, before taking it to the mechanic. Between this and the OBD meter I bought, I saved probably about $1k vs taking it to the shop.