They are havng some SERIOUS issues with the 6.4!! There is a leak somewhere, and drips on the exhaust manifold; therefore shooting flames out the back. I heard so far that there is a software fix. THAT would NOT be good enough for me!!
My 6.0 PSD has some serious turbo lag. My truck couldn't get out of it's own way!! My 6.0 PSD also stranded me twice!! I have since gotten rid of it!!
Its not a leak. Thanks to our tree hugging friends and the EPA all diesels manufactured after january 1st of this year are required to have a particulate filter in the exhaust. This filter eventually becomes overloaded with soot, and has to go through a regen cycle to burn itself clean.
During the regen cycle there is an extra fuel injection event taking place beyond the normal timing of the engine in order to introduce raw fuel into the particulate filter and burn off the soot. During this regen cylce the exhaust temperature climbs to over 1000 degrees (which is the reason for the venturi tip they have now) and fuel mileage drops ridiculously.
Some of the early 6.4's had an issue with the regen cylce causing fire to come out of the tailpipe. This really isn't that surprising when you consider the way the system is now required to work. From what I have heard, the programming for the 6.4 has been updated since its induction and many of these problems have been worked out.
Since the 6.0 powerstroke was mentioned, it might as well be pointed out that many of the issues involved with the 6.0 powerstroke stemmed from emissions requirements and the use of an EGR valve and cooler set up. When coasting, the EGR valve opens and exhaust gases are run through an exhaust cooling manifold and then back through the system. This includes running exhaust gases back through the turbo charger which can clog the vanes of the turbine and make them stick and causing overboost, or lack of boost depending on their position. The EGR valve itself can also stick causing lack of power and boost. There were also problems with the EGR cooler boiling and causing coolant to puke out of the overflow/degas bottle for the radiator.
In the later model years of the 6.0 many of the previous problems were resoved and more of them probably would have been had it not been forced out of production by the mandate for particulate filters and lower emissions at the start of the year.
While the cummins diesel does have an overall better reputation than the internantional motors used by ford, they fall under the same regulations and have many of the same problems. You can't get a new truck with the old 24 valve 5.9 liter cummins in it any more, and the new motors have their share of problems. And while it mostly comes down to personal preferences, I find Ford trucks to be better overall than Dodge. You can buy a truck or you can buy a motor, I consider the whole truck.
As far as the 6.4 powerstroke, I haven't personally driven one but have read quite a few favorable reviews. Its supposed to be much quieter and offer plenty of power. Thanks to common rail injectoin instead of the HEUI injection of the old motors, as well as the dual sequential turbo chargers it is also supposed to be a much more responsive motor with less lag. I never felt the lag on the 7.3 liter was that bad, but it is fairly noticeable on the 6.0. Both of the old powerstrokes would pull whatever you put behind them though. I've personally towed over 10,000 lbs with them and never felt underpowered. I'm sure the new motor will be even better.
I just wish the damn government would quit trying to regulate the rate we develop technology at. Everytime you start to get a decent motor they up regulations and force manufacturers to put out some untested half assed idea in order to stay in business. There is actually talk of a bill to mandate ALL vehicles average 30 miles per gallon by a certain date, and meet all the emmisions regs as well. If they can make laws like that they ought to mandate that cancer be cured by 2010 too.
