In your car’s engine computer, chips hold the programming data that the computer uses to interpret input signals and control output devices. If you have the proper equipment and knowledge, the programming on the main chip in your car’s computer, the PROM, can be changed to improve performance and economy. The easiest way to tune your car’s computer for performance and economy is to buy a chip that has basic performance parameters pre-set, and then install a programming module inline so that you can make changes live or on the fly as you’re driving.