No power and Blue smoke... but only sometimes

[Montana250]

I have an ’05 F250 6.0L and periodically (maybe once every 2 days) when I try to accelerate from a stoplight it will just bog down and barely move, won't go above 2000 rpm and, there will be a cloud of blue smoke coming out the exhaust. I have put it in neutral and revved the engine and that seems to make it “snap out of it” and return to normal operation. Its almost like a light switch is being turned on. One second it can’t even move and its billowing blue smoke, the next its running 100% and has all the power in the world.

Any Ideas? A buddy of mine said that next time it happens to unplug the EGR valve and see if that fixes it. Unfortunately/fortunately every time it happens it has gone away in a matter of several seconds. If it does it again I may unplug the EGR valve and drive it like that for a week or so seeing if it repeats. Is this a good idea?

I am not incredibly familiar with the turbos that are on these 6.0L’s but I do remember somebody saying they are variable geometry so to allow them to spool quickly and run as effectively as possible. Would this symptom I am seeing be consistent with a failure of the turbo actuator? (if there even is such a device) If there is no actuator, what controls the pitch in our turbo inlet guide vanes?

I have not noticed any repeatable circumstances that bring this situation on (some days its hot outside, some days its cold… etc.) I have also not noticed what the turbo was putting out when this occurs. If it occurs again I will be sure to see if i'm getting any boost at all.

THANKS FOR THE INPUT!!

[dannyboy950]

Diesel Technician Society this link will take you to some good general turbo information as well as how to clean it.
Turbo is most probable cause. Altho other things can be happening as well.

[Montana250]

RESULT

It was the EGR valve. The truck was acting up repeatedly one day, I unplugged it (that was about 2 months ago) and it hasn't done it since.