Hi all,

The other day my 03 F-150 Lariat FX4 5.4, Automatic felt sluggish when accelerating, and then I noticed that it hadn't downshifted from D to 2 when getting on the gas.

It only does this after driving for maybe 5 or 10 miles, so after the tranny gets hot. When cold it operates normally. It shifts just fine going upward and reverse is OK too. It is only downshifting when hot issues.

The fluid level was maybe a quarter to a fifth of a quart low so I added some Mercon V which has not made any difference.

Any thoughts?

 

So...
Does it downshift when you are off the gas and slow to a stop?

D

 

After I come to a complete stop, say a stop light, then accelerate it appears to be in first and shifts normally, until I slow down and then try to speed up again, then no downshift.

 

I would love to see what the computer is commanding and why. Too bad you don't have a way to datalog it.

Makes me wonder about the throttle position sensor or maybe even the transmission range sensor.

Are there any other symptoms or weirdness going on? Did anything change or get changed on the vehicle close to before this started?

D

 

No weirdness prior to this, no, it was fairly sudden.
I have only owned the truck for a month and it has always shifted kind of hard from first to second and then mushy from second to third.

It does idle kind of rough but my mechanic told me the 5.4 just does that...???

No check engine lights no OD flashing etc - it does downshift out of OD on the freeway though. just not from third to second, second to first.

If I am going, say 50 to 55, and then turn the OD off, it does downshift on its own.