GMC 2008 Envoy - Manual (Page 299)

If you want to do some of your own service work, you
should use the proper service manual. It tells you much
more about how to service your vehicle than this
manual can. To order the proper service manual, see
Service Publications Ordering Information on page 7-16.
Your vehicle has an airbag system. Before attempting to
do your own service work, see Servicing Your
Airbag-Equipped Vehicle on page 1-66.
You should keep a record with all parts receipts and list
the mileage and the date of any service work you
perform. See Maintenance Record on page 6-16.
Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the airflow around it. This can cause wind noise
and can affect fuel economy and windshield washer
performance. Check with your dealer/retailer before
adding equipment to the outside of your vehicle.
Fuel
Use of the recommended fuel is an important part of the
proper maintenance of your vehicle. To help keep the
engine clean and maintain optimum vehicle
performance, we recommend the use of gasoline
advertised as TOP TIER Detergent Gasoline.
5-5