White smoke out of tailpipe

I have a 04 Durango with 155000 miles. I hade a full
diagnostics test whitch showed the code for multiple mis
fire in multiple cylinders so I changed all spark plugs and
the 6 and 8 ignition coil and the 8 fuel injector.( all i could
afford at the time of purchase). After i changed them my
check engine light turned off but p0113 code came up so i
changed my intake air sensor but the cod is still showing
and the white smoke continued. Now my truck is idling
rougher. My oil is not milky, the engine isn't overheating'
my coolant, oil, and transmission fliud are still at normal
levels. What could be the problem and can i do it my self?