1998 GMC Sonoma Owner's Manual - Page 329

Maintenance Schedule I Long Tripmighway Intervals I Long Trip/Highway Intervals Every 60,000 Miles (100 000 km): Engine Accessory Drive Belt Inspection. Fuel Tank, Cap and Lines Inspection. Every 100,000 Miles(166 000 km): Spark Plug Wire Inspection. Spark Plug Replacement. 4.3L Engine Only: Positive Crankcase Ventilation (PCV) Valve Inspection. Every 150,000 Miles (240 000 km): Cooling System Service (orevery 60 months, whichever occurs first). I Every 7,500 Miles (12 500 km): Engine Oil and Filter Change (or every 12 months, whichever occurs first). Chassis Lubrication (or every 12 months, whichever occurs first).Drive Axle Service. Tire Rotation. Every 15,000 Miles (25 000 km): Automatic Transmission Service (severe conditions only). Every 30,000 Miles (50 000 km): Fuel Filter Replacement. Air Cleaner FilterReplacement. Front Wheel Bearing Repack (2WD only) (or at each brake relining, whichever occurs first). Every 50,000 Miles (83 000 km): Automatic Transmission Service (normal conditions). 7-7