1993 GMC Suburban Owner's Manual - Page 343

Engine Description 4.3L VGTTBI with 8500 GVWRand below with 8501 GVWRand above H K Emissions LD HD LD C J F N 5.0L V8/TBI 5.7L V8/TBI with 8500 GVWR and below with 8501 GVWR and above 6.2L V8IDiesel 6.2L V8/Diesel 6.5L V8/Diesel 7.4- V8/TBI ,Except 454 SS Model with 454 SS Model LD HD LD HD HD HD LD TO268 NOTE: TBI is a throttle body injection system. Selecting the Proper Maintenance ScksduBe Here is how to tell whichschedule to follow once you find the proper maintenance chart to use. MAINTENANCE SCHEDULE I Is any one of these true foryourvehicle? Q Most trips are less than 4 miles (6 kilometers). Q Most tripsareless than 10 miles (16 kilometers), and theoutside temperatures are below freezing. The engineisat low speed most of the time(as in door-to-door delivery, stop-and-go traffic, or commercialuse). You operate in dustyareasor You tow a trailer off-road frequently. 0 Q Q If any one (or more) of these is trueforyourdriving, follow Schedule I. Schedule I is shown by a plus sign (t)on the chart. MAINTENANCE SCHEDULE II FollowSchedule II ONLY if none of the aboveconditionsaretrue.Schedule II is shownby a dot (0) on the chart. 7-5