Why would mileage and heat index and trip miles and miles to empty light change.

Hello, erratic electrical outputs and display readings are often influenced by low battery and vehicle voltage. Check the status and condition of the battery for the power on hand and the ability to sustain a load. Other than that, additional hands on testing is required at a local repair facility near you - no way to know anything without testing. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops