Hi,
My truck sometimes at WOT hesitates at 3200 rpms. It will hit 3400 then back down to 3200 then creep back up to the shift point rpm. It doesn't do it everytime. Any thoughts?

Thanks
Darren

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97' F150 Lariat S/C long bed 4x4 3:55LS 4.6L auto...SuperChip, 40 series Flowmaster cat back.
Colorado Springs, CO

 

Mine does that to. It seems like it is the torque converter slipping while it is reving 3400 then it locks in when it drops to 3200. Just my thought. It is constantly picking up speed so it is not like the motor is loosing power.

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1997 4x4 5.4 ORP XLT extended cab Dark Toreador red Westin nerf bars tint HARDER THAN A ROCK AND FASTER THAN A HEART BEAT

 

Is the torque converter locked and unlocked by your computer. Maybe thats why, sometimes it thinks it needs to unlock and lock at different times. Remember I am just guessing hear now. That was the only thing I could come up with, because my speed is going up even when the rpms are changing. So to me it doesn't seem to be the motor.

 

If it were the converter, why does it do it only once in awhile? Seems that it would do it everytime if it were the converter. I think it is in the motor. I have 48k miles on the truck. Could it be a dirty fuel filter?

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97' F150 Lariat S/C long bed 4x4 3:55LS 4.6L auto...SuperChip, 40 series Flowmaster cat back.
Colorado Springs, CO

 

I've noticed this on my truck as well, although it's more of a "sag" in the power output of the engine. After a little research at the Ford website, I found a graphic showing the horsepower and torque curves for the 4.6. There is a rather dramatic "dip" in the torque curve (about 50 lbs ft), starting about 3200 and ending about 3400 r.p.m. This may be a function of the secondary passages in the intake manifold opening (which is supposed to occur around the 3K r.p.m. point).

my .02

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'98 F-150 4x4 XLT SC/SB, 4.6L automatic, Dark Toreador Red / Prairie Tan, Westin step tubes, Gibson Swept Side, K&N w/ custom box, Autometer pod and gauge assy and other cool stuff...