check engine light on 04 xls awd

[donkeeh1]

So I got a check engine light and I got it read and it says that cylinder 5 is misfiring...so I changed all the spark plugs plug wires and all three coil packs...oil change done as well drained the oil for about 3-4 hours while I was changing out the said above...after all that work the check engine light comes back on...oh and b4 I replaced everything I forgot to mention that there is white ish smoke that comes out of the tail pipe...and it's STILL doing that...so is a rebuild in order here??? Or is there anything else I could do??? Please help...and thanks in advance

[dclambertt]

See what the smoke smells like to help diagnose. Whitish smoke tends to be coolant, and a sweet smell might indicate that's what it is. Burning oil smells quite different. Possibly a head gasket went south at cylinder 5?