1997 GMC Sonoma Owner's Manual - Page 345

I Short TripKity Maintenance Schedule I 100,000 Miles (166 000 km) 0Inspect spark plug wires. An Emission Control Service. 99,000 Miles (165 000 km) 0Change engine oil and filter (or every 3 months, whichever occurs first). An Emission Control Service. 0Replace spark plugs. An Emission Control Service. 0Lubricate chassis components (or every 3 months, whichever occurs first). (See footnote #.) 0Check readfront axle fluid level and add fluid as needed. Check constant velocity joints and axle seals for leaking. (See footnote *?) 0Change automatic transmission fluid ana filter if the vehicle is mainly driven under one or more of these conditions: - In heavy city traffic where the outside F temperature regularly reaches 90 O (32°C) or higher. - In hilly or mountainous terrain. - When doing frequent trailer towing. - Uses such as found in taxi, police or delivery service. I DATE I ACTUAL MILEAGE ISERVICED BY I (Continued)