If it's anything like the gas engines, it's misfiring all the time, you just don't notice it till it gets into O/D. I don't know enough about diesels to even begin troubleshooting though...

Yeah....compression ignition changes everything. I think you're looking more at a fuel delivery problem....bad injector(s), tired injection pump, water in fuel, clogged fuel filter etc

Tx guys, I have ordered two new fuel filters, I use Baldwin filters and change them every other oil change...I'll keep looking and post if I find the problem...

On our '02 the relay for the VP44 gets hot and then gets flakey, but we get a code for lost comm with VP44. It's never caused intermittent "misfires" for us but more like limp mode