My problem child is a 2004 6.0L with 210K miles. I replaced the turbo several months ago, and just this past week was forced to replace the HPOP. And with that last item I think the current story begins.
My problem seems to have started during a fuel starvation event.
Per the dealer, this oversight killed the HPOP which they kindly replaced ($2400, as I was 300 miles from home). When I got the truck back, I drove home from the dealer and the truck was absolutely flawless for 300 miles. Honestly, it felt the best it has ever felt since I bought it at 150K miles. Smooth, responsive, and just a joy to drive.
This AM (in 60F weather) it starts-up on the second or third turn but is VERY upset. It has a rough idle with a heavy miss for several minutes. Driving it when the gauge is cold reveals it has no power whatsoever and it develops a really pronounced miss at 1500 rpm and above. This miss gets progressively better (smoother) as it warms-up. With the engine at normal operating temp after 20 minutes of gentle driving, the symptoms are largely gone. It idles fine, drives OK, but if you put your foot into it, it feels like its starving for fuel or being strangled. The engine just won't wind-up above 2700-ish RPM, and when it does suddenly "snap" into making some power, it surges... and then goes back to the missing/starvation act. (Feels exactly like hitting a soft-touch rev-limiter on a gas engine). Also, I notice the 2-3 shift point is displaced upwards in the RPM band and most times the engine misses just before the shift. The funny thing is, if you keep your foot out of it, once it's warmed-up, it feels pretty normal and drives OK. Warm, it will start fine, idle fine, and mostly behave itself. Cold... it's just a miserable beast. There are no check engine lights or outward indications of a failure. I'm looking for a scan tool to borrow and will report what I see if I can get my hands on one.
Any idea what gives here?
I was referred to this forum by a co-worker and would love to know your thoughts. I'm not exactly a noob when it comes to diesels, but most of my knowledge involves ag equipment with green paint, IDI, and production years beginning in "19", so you've been warned.
Thanks in advance for any insight you may have!