My fathers car has had this low power, turbo lag light flashing on dash problem for 1 year now, As it was out of warranty, we never bothered!
The power loss and turbo lag became so bad we had to fix it.
It was a dog on take off, then at 2500 rpm, it took off when the boost cut in, which shouldnt happen, as it has new design variable turbo pitch, which means boost should be constant right through the rev range.
After changing the fuel filter it seemed to go away, but a month later would come on again, or when stomping it up a big
hill.
We checked all the fault codes ourselves by counting the flashes on the dash by shorting a terminal out under the dash, which you can do as
well, just get a gregorys manuel, and its step by step.
The throttle sensor and pressure sensor came up, but when we stripped and tested them they were fine.
Jason from Nissan in Granville came to our rescue, and said the actual turbo might be the problem, as theyve changed several already.
He plugged his computer in and couldnt find any problems, turbo wasnt changed.
We took a stab in the dark and changed the AIR FLOW SENSOR, and guess what, it spun the wheels again!
No computer would pick up the fault with the sensor.
If your trucks still under warranty, get them to change it, as we havent bought a new sensor yet, and are working on getting it under warranty, as ours is run out.