it runs great but didnt pass emisson test

True key to start potion 4x4 lights come on then imedetle turn off

problem just started after I left the rear doors open after unloading

Not getting proper signal from ckp.removed it and found engine oil on normal

Trying to remove to replace got in fender bender and have leak needing to remove

When I put yukon in gear forward and reverse it makes noise !put in new transfer case and does it still! !only now have no park or reverse! !!!!what could be the problem? HELP

Water in my oil if intakes cracked can it also get in the cylinders plugs damp 3rd cyl. On drivers side