My most recent experience with Berryman B-12 ChemTool. I have a 2003 Volkswagen with a 1.8T engine with 141,000 miles. In the last 2 months I replaced the spark plugs and air cleaner. In the last week or so it started idling roughly on start up. This would last approximately 15 to 30 seconds then seem to stop. It did seem to be worsening as the rough idle would cause the check engine light to flash. Monday morning (10/26/15) I poured one can of your B-12 into my ¾ full gas tank. Upon starting the engine, it again idled very roughly, the check engine light flashed then it went away after a short time. I drove to work as normal that day. My trip to work is approximately 22 miles roundtrip, mostly highway (speeds of 45-65). Tuesday morning I started the car and the rough idle was gone!
I realize that critics could say that this proves nothing. I don’t know what the problem is/was. Since I don’t know what the problem is/was, I have no way of knowing if it’s fixed. The problem may return. The problem may have been electrical or mechanical, having nothing to do with the fuel system. The problem may have been excess water or “bad gas” and any cleaner might have fixed it. There is no way of knowing if the problem would have self-corrected without the addition of any product.
I believe that your product did fix the problem. What I like about your ChemTool is I can purchase it for just over $3 at WalMart. Some cleaners cost 4 times that much.