The firing order for a 1992 Chevy Suburban depends entirely on the engine it has. Suburbans in 1992 came with several different engine options (like the 5.7L, 6.5L diesel, and possibly others). You
must know the engine displacement (e.g., 5.7L, 6.5L) to determine the correct firing order.
Once you know the engine size, you can find the firing order in your owner's manual or a reliable online automotive repair resource like a Haynes or Chilton manual specific to your vehicle's year and engine.