I have a 01 F-150 with the 6. It gets 18mpg and goes along great with the auto trans. I have a problem, when I am cruising and come up to a incline and give it a little gas it stumbles and then you have to give it more gas, then it down shifts and goes along fine after that. Does anyone know why it could be stumbling? I had a 97 as a company truck and had the same problem except it always did it off the line only. It was the coil pack. The dealership said if the check engine light is not on then they would not be able to troubleshoot it. I have changed the air filter, fuel filter and cleaned the injectors. It still does it. Great truck, engine, and trim level, the stumbling worries me. Can anyone help?
Thanks.

 

I'm guessing it could be your fuel filter. It may be clogged up, starving your engine from gas. Also have your fuel pump checked out. It could be going bad. Or you could just have a fouled plug or a bad wire. Check all those out.

 

Might you also describe this a a small jerking motion? Like a lunge front and back? Mine is doing this anywhere after 50 mph. Possible speed sensor problem.

 

I have replaced fuel and air filters, I have not tried the plugs or wires yet. It does it at all speeds but only when you have to give it gas to go up a hill, when a downshift is needed. It is like I have to give it more gas than usual to get it to go. Maybe I am not driving the truck properly. But I will replace the plugs and wires.