The automatic display of your credit card is not about www.kevadiesel.com, but about the settings of your web browser (Explorer, Firefox, Chrome, etc.).
To turn off this feature; Turn off the automatic form filling section by going to "Tools / Internet Options / Content / Auto complete” (Tools / Internet Options / Content / Auto complete)
This is not a problem if you are only using your computer. However, if you have more than one user on the computer, please do the above.