Since you didn't give the much detail like the Year. For a 1999
Suburban it is 1-8-4-3-6-5-7-2.
As you look at the engine from the front.
Left side is 2-4-6-8
Right side is 1-3-5-7 [http://autorepair.about.com/od/enginefiringorders1/Engine_Firing_Orders.htm Go here to look it up] Good Luck and Remember.
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