need a capacitor for small electricals?

I have a wideband unit in my car which has failed several times. My guess at why is that when I turn the car off, my turbo timer kicks on. When this happens, I can watch the wideband display turn off for a split second and then turn back on and go through a reset. I am assuming there is a brief period of power loss when the turbo timer kicks on. Would a capacitor eliminate the power loss to my wideband unit? If so, how do I know what type of capacitor to use and how do I wire it in. I do not typically use them at all. Thanks for the help and any advice.

What is a wideband unit?  and how much current does it draw?