Originally Posted by Father Of Giants

So much so I only take the highway at night or before dawn.

Two more odd issues.

#1 in gears 1-2 At full throttle the cat will not go past 4300-4500 rpm. It will hover at 4500 and not up shift.

#2 in gears 3-4-5, at full throttle the car goes into neutral. Which makes it not suitable for highway driving.

When I am normally putting around it acts fine.

Why is it doing this? Bad transmission, bad kickdown, faulty transmission electronics, or simply clogged fuel filters?

I'm scheduling a 6 can diesel purge sometime next week. Maybe that will help.