I get a faint cloud of smoke but nothing heavy.

Black smoke? A stock truck shouldn't be putting out any smoke.

It could be the turbo just sticking up on you, quite common. Before diving into that, I would first try and clean the EBP sensor and tube. On the drivers side exhaust manifold towards the front cylinder, looking from the top you'll see a stainless tube threaded into the manifold itself. Follow this tube up, at the other end you'll see a sensor plugged in. This is the EBP, or exhaust back pressure sensor. It monitors the pressure feeding the turbo. It can be monitored on a scanner as well. I would remove that sensor, and the tube it's attached to, and clean both really well. They gum up from soot and what not over time and then start sending funny signals. Also inspect the wire harness going to the sensor itself. This is a simple and quick project so it's a good place to start. If that pans out, might be time to yank the turbo and give it a cleaning... which you can see how to do right here: DTS Articles - Turbocharger Reconditioning
Also may be worth pulling the EGR valve and cleaning that if it hasn't been done in a while.

:c: