Cross Spark Plug Wires?

I have a "97 M C Z34, and after I washed it it bogged down real bad, and backfires alot.
After changing plugs, coils, and wires, it runs just as bad as before.
Could I have the wires crossed? And if so How do I get the firing order.
Thanks

the firing order is 123456 on all gm 60 degree v6's

You can go to the nearest Library and they should have automotive manuals that give a picture of firing order and where wires are placed for your car.The original wires has a # on them and a # on the coil packs that match.If you replaced the original wires this might help to find the correct firing order.Also if you are looking at front side of engine with the hood open from left to right the wire are 2-4-6 and the back cylinders rom left to right are 1-3-5 and these should match with the coil packs #1 to 1 cylinder wire #3 to 3 cylinder wire ect.Starting withe coil packs from front of car to back of car should be #5 #2 #3 #6 #4 #1 This is the setup on my 1996 Monte Carlo 3.4.Hope this helps.