I have a 2004 f250 6.0 That feels sluggish and requires lifting off the accelerator to upshift, if not then it seems not to shift until 3k or more rpms. After driving for about 20-30 minutes the truck will start bucking and trying to stall while driving. Sometimes if I pump the accelerator the truck will try to stay running, but sometimes dies requiring to come to a full stop and place in park to start back up. I plan on getting it to ford to have it looked at, but was wondering if anyone here has any ideas? There is also no check engine light being thrown at all.

 

Has the tranny been serviced at the 30,000 mile intervals with SP or LV fluid and the ext. filter changed?

 

I have no idea if it has or not before I owned it. I bought the truck used a year ago and have put a little over 1000 miles on it since it's not my daily driver. That was one of the things I was thinking of doing first.

 

The 6.0 and tranny are robust units but require **** maintenance. I would start by changing all fluids and use only OEM filters. Stay with SP or LV in the tranny. I'd also go with the 5W40 oil since you have no idea about the past maint. history. You need a starting point on the maint. You'll also need a monitoring system such as a ScanGauge ll at a min. to see what's going on with the engine and electronics, mainly the ficm and temps. The factory gauges are no better than idiot lights.

 

That's the route I'm going to go especially since it's the cheapest and the best thing to start with. Thank you for the help and info.