Turbo vane position sensor going out??

the first thing i would do seeing you have a k&n is clean the MAF. buy a can of MAF cleaner at a parts store and follow the directions on the can. it's really easy and the oiled filters like k n can suck oil onto the sensor and skew airflow readings resulting in loss of power and smoke

 

I had a similar problem with my 2004.5 lly. I had the wire harness to injectors replaced (known problem among the lly engines) because it was over fueling. Still lacked power in over drive. It ended up being a dirty fuel filter, only about 2k miles on it.
I have found that the WIX filters are the best.

 

it was my MAF sensor thanks lddrew. lot of help and save on the heartache

 

When you have an oiled air filter-- like K&N, it can deposit oil on the MAF sensor and cause erratic MAF readings. Many have changed back to a paper filter because of this.

 

My 06 is doing this randomly too, I am going to clean the MAF first then check the fuel filter if that doesnt clean it up. I have a can MAF cleaner waiting to be used but so little time, even on my week of "vacation"