Bests & Worsts Reviews from Amazon

This is my story. My Honda Odyssey EX-L 2005 (85K miles, first owner, bought new, all regular maintenance) all of sudden had a CEL light on 11/22/2016. It threw a code of P0420 pointing at catalyst system efficiency below threshold (bank 1). Based on my research, there are too many things that can cause this code. However, if it comes to the catalytic convertor or oxygen sensor replacement, the expense could be too high. So, I decided to take care of it myself before I go to Honda dealer or other mechanics. I first changed the engine oil at Walmart, just regular Quake 5w20 oil. Besides, I asked the technician at Walmart to add a bottle of Lucas (heavy duty Oil stabilizer, white bottle) as well because the engine seems to burn a bit oil over time. I also filled the gas tank up (regular 87 gas) and added a bottle of Heet (red bottle, Heet Fuel Line Antifreeze, Water Remover and Fuel Injector Cleaner) into the gas tank to remove water and hopefully to clean the fuel injector. Then I cleared the code myself and started driving the vehicle locally. After driving about 135 miles, the engine light was on again and had the same single P0420 code. At the time, the Cataclean I ordered from Amazon arrived so I want to give it a shot. At this weekend (12/03/2016), I already drove the car for about 190 miles since I filled the gas full. I poured the whole Cataclean into the gas tank, which had a bit less than a quarter tank of gas. Then I drove on to highway. As some reviewers suggested, when there were no cars close to me, I stepped on the gas pedal hard (almost 'floored' it) to get RPM to 5K. When the RPM reached 5k, the speed of the car was about 85 miles on highway and then RPM immediately fell back below 4k and 3k itself. I released the gas pedal to slower the car. (If you do that as well, do be careful. Nobody wants to get a speed ticket on high way, right?). I did the same cycle for about 5 times on highway: slowing down to about 60 miles/hr -- flooring gas pedal to reach 5k RPM (speed over 80 mile/hr) -- releasing gas pedal to let the car slow down. After driving about 30 miles, I stopped in front of a mall to shop a while. About 15 minutes later I came back to the car and started it. You know what, the engine light was off, on its own! I drove another 40 plus miles after that and stopped at a gas station to add some fuel. I just added 6 gallons of regular 87 gas. As I do not plan to add premium gas in the future, I did not want to do it now as some reviewers suggested. With 6 gallons of fuel, I drove more than 120 miles before I filled the gas tank again. That 6 gallons of gas gave me about 21-22 miles/gallon gas mileage, which was about right for Honda Odyssey. The engine light is still off (after driving 170 miles). I felt the car was getting more power after adding the cataclean. The acceleration was smooth and more powerful. I did not observe any black smoke (or any kind of smoke) from the tailpipe when I floored the gas pedal. The car did not have any driving issue or noise or anything. I did not expect it worked so well when I did not see any smoke or anything coming out of the tailpipe. But obviously it helped clean the catalytic convertors or oxygen sensors or whatever that threw the P0420 code. I am not sure how long the code will be off and I will post a follow-up comment in the future. Again, the car has been maintained regularly for oil change, transmission flush, and I added sea foam to gas, oil gasket, and even brake air intake lines once every other year. However, the car was driven mostly local in the past 4-5 years. I can tell you, its RPM never reached 5K in the past 5 years. What causes the P0420 code? I do not know. But obviously the Cataclean did help at this time. Spending $16-20 on the Cataclean before you touch the expensive oxygen sensors or catalytic convertors could be a good investment. I plan to buy another bottle in case the code comes back again. Good luck to you DIY maintenance.