I have been driving with a Fluidampr for a couple months over several thousand miles. I have a lot of cold morning starts so I rev the engine to bring up the temperature. Every time I drive my truck I am amazed by how much smoother the engine now runs. The improvement is noticeable from idle, but is most impressive between 2,000 and 3,000 RPMs and continues to be just as smooth to 4,000 RPMs. Even the sound of the engine is different, less clanging, more like a big block gas engine. Had I known my engine would run this much smoother, I would have installed a Fluidampr years ago.