Your 1997 Kia Sportage 4x4 temp gas and tach go up and down like crazy. Also the lights in and out of the car dim on and off please help?

check the alternator wires to make sure they are tight remove wires from the battery and clean the contact points both on the battery and the wires scratch them up good so that you have shiny metal whare thay contact check for a loose ground either under the hood or under the dash make sure they have clean contact points if that dont do it look for any loose or damaged wire my guess would be a loose or bad ground wire