There are many fraudulent products on the market which claim to improve your fuel economy. They come in various shapes and forms. For example:
- Electronic gizmos with flashing lights that you plug into the diagnostic port or cigar lighter socket.
- Liquid or solid additives that you put in the fuel, or oil
- Special air filters, housings or ducts.
- Fins that you affix to the body of the vehicle.
None of them work. Cars already come maximally optimized. There is very little that can be improved upon and the last 1% of energy theoretically available isn't worth spending money towards.
See our topic page all about fuel saving scams here.
Statement issues by GM, warning people about "miracle" products.
Note: GM recommends against putting acetone in your fuel tank.
Link: Service Bulletin 05-00-89-072E (March 2022) Maximizing Gasoline Fuel Economy (PDF document)