I also have an '04, now with 120,000 miles on it.
It will not get out of it's own way when first started. It definitely does not like cold weather.
It turns out that my thermostat was sticking open, the truck would never truly warm up. It was only getting to ~160*F, it should run at ~190*F. After changing the thermostat it runs much much better after getting warm.
I'm gonna give you a good piece of advice about that 6.0 Ford motor. They are good engines, but only after they are "fixed" from their factory state. There aren't a whole lot of things you can do yourself these days but I highly encourage you to buy a plug-in monitor like the Edge Insight to monitor certain parameters of the engine.
You really need to watch your ECT/EOT temps. ECT = Engine coolant temp, EOT = Engine oil temp. Those trucks have an oil cooler (right on top of the motor) that is VERY prone to plugging. This and the EGR on these trucks are their Achilles Heel.
When your ECT/EOT delta gets to about 15 or more degrees it's time to have the cooler replaced. If you don't do that you either rupture the cooler and end up with oil in your water or water in your oil. Worst case is you pop a head gasket. Replacing the cooler is about a $1500-$2500 job at a mechanic. Engine coolant runs about 190*, Engine oil should be no more than 10-15* above that.
With an edge insight you can monitor your ECT/EOT delta (difference), FICM voltage (should be 47.5V), turbo boost, fuel mileage, etc. It's not a cheap unit, they run about $300-400 and they plug into the OBD II port. I think I saved several hundred dollars already on mine because I was able to see that I was running cold (Ford gauges have no numbers) and that my turbo boost was running low. I was only building 12 psi of boost max when I should be running 25-28 psi. It turns out I had a hose coming from the turbo with a hole in it. After replacing the bad hose I was building my full boost, it was like driving a different truck.
The truck is still sluggish when warming up but warms up much quicker and runs much better after warming up. The Edge Insight will even check and clear any codes you may have.
It will not get out of it's own way when first started. It definitely does not like cold weather.
It turns out that my thermostat was sticking open, the truck would never truly warm up. It was only getting to ~160*F, it should run at ~190*F. After changing the thermostat it runs much much better after getting warm.
I'm gonna give you a good piece of advice about that 6.0 Ford motor. They are good engines, but only after they are "fixed" from their factory state. There aren't a whole lot of things you can do yourself these days but I highly encourage you to buy a plug-in monitor like the Edge Insight to monitor certain parameters of the engine.
You really need to watch your ECT/EOT temps. ECT = Engine coolant temp, EOT = Engine oil temp. Those trucks have an oil cooler (right on top of the motor) that is VERY prone to plugging. This and the EGR on these trucks are their Achilles Heel.
When your ECT/EOT delta gets to about 15 or more degrees it's time to have the cooler replaced. If you don't do that you either rupture the cooler and end up with oil in your water or water in your oil. Worst case is you pop a head gasket. Replacing the cooler is about a $1500-$2500 job at a mechanic. Engine coolant runs about 190*, Engine oil should be no more than 10-15* above that.
With an edge insight you can monitor your ECT/EOT delta (difference), FICM voltage (should be 47.5V), turbo boost, fuel mileage, etc. It's not a cheap unit, they run about $300-400 and they plug into the OBD II port. I think I saved several hundred dollars already on mine because I was able to see that I was running cold (Ford gauges have no numbers) and that my turbo boost was running low. I was only building 12 psi of boost max when I should be running 25-28 psi. It turns out I had a hose coming from the turbo with a hole in it. After replacing the bad hose I was building my full boost, it was like driving a different truck.
The truck is still sluggish when warming up but warms up much quicker and runs much better after warming up. The Edge Insight will even check and clear any codes you may have.
