Ddec6 turbo speed code

[tree98]

it's possible your exhaust is plugged somewhere, that can cause the symptoms your having. unhook the pipe from the back of the turbo and see if that fixes it. I had a truck with intermittent low boost one time. I took it to a local shop and right away he says it's either a plugged exhaust, the boost sensor or the turbo. He holds his hand up over the exhaust outlet while it was running and says " feels fine it's not plugged" I said ok replace the sensor because obviously thats the cheapest and easiest thing to to. He changed the sensor and it was fixed, well seemed like it anyway. couple days later the same thing again low boost,low power,cel. Back to the shop it went, this time he couldn't get it to act up. He drove it and drove it and it ran just ran fine! So i go get it and on my way home on the freeway it starts slowing down and cel comes on, at this point i'm getting really aggrivated with this stupid truck so I ripped the doghouse off while going down the road(sterling chassis they come off easily) not really knowing what i'm looking for but i get it off and i see the exhaust manifold and turbo are glowing red because they are so hot! I pulled over and got out,walked around to the exhaust stack and i could actually hear air pissing out(was actually compressed) of a tiny hole by a clamp for the pipe going into the bottom of the muffler. Right away i knew the stack was plugged.So just because you feel exhaust coming out the top of the stack, it doesn't mean ENOUGH is coming out, your hand is not a pressure sensor. In this particular case the stack was a catalytic converter style and was breaking apart on the inside. So it was intermittently blocking some of the exhaust flow until I hit the right bump or something to rattle it out of the way. Changing the boost sensor didn't do anything it was just coincidence that the exhaust restriction got moved out of the way somehow between the time we were test driving and when it was installed. This may not be your problem at all but I thought I would share my experience. This was also a big reason i started working on my own trucks. It just seemed like I ended up fixing or re fixing my truck anyway and still had to pay those clowns.