P0300 / Bad Crank Tone Wheel
Earlier this year my truck was giving me all sorts of trouble. Starting with a P0308 and a P0300, which is injector misfire #8 and multiple random misfires respectively. When i replaced the #8 injector the code went away. My truck would always start up in the morning but would run rough and die if i hit the accelerator while pouring out white smoke. After the truck was warmed up the smoke quit and could actually drive the truck, albeit with a slight miss in the injectors. At this point I was gearing up for a full stud job in my driveway, knowing i had a cracked head. I took my truck to the local diesel shop so they could hook it up to the IDS to help me diagnose what is going on. While trying to run a relative compression test my truck would kick the test off before it would start. They told me to try a new cam sensor so i did, retried with no luck. So im off to do my head gaskets and reman'd heads from the machine shop. I get my truck all together, started it up and bam i heard a pop through the intake. No big deal, i replace the rocker arm and push tube. Now my truck won't start at all. I ended up taking my truck to lead foot diesel to have them take a look at it. Turns out the tone wheel on my crank is loose.
To make a long story short, if you have a P0300 code run a relative compression test and see if it kicks you out. If it does, chances are your tone wheel has slipped.
After fighting all this in the last 5 months, i let my girlfriend borrow my truck yesterday and now its at the Paul's transmission getting a rebuild.
Hopes this helps somebody out.