jerky between 40-45mph
 

I have a 2000 F-250 CC,SB,4x4 PSD auto. While driving between 40-45mph and around 12-1300rpms my truck jerks back and forth. It seems like the truck does not know what gear it wants to be in. If I slow down to less than 40, or faster than 45 I have no problens at all. Has anybody else experienced this? I don't think it is anything serious, just annoying. Thanks.

Well, I had a similar problem with my 1997 7.3L 4x4 F250 at somewhat lower speeds. Basically, second gear was gone, so it would rev very high in first (almost red-lining) then try to shift into second around 25mph with an audible clunk, and then immediately shift to third, which made the truck buck like a bronco. The transmission specialist I took it to said it needed a completely rebuilt transmission. But in my case the truck had 148K miles on it, and I didn't have to pay for the new transmission.

Thanks for the reply. There are no rough shift sounds or anything like that, it just feels like the truck is confused(hard to explain). It seems like whatever gear it is in(between 40-45mph and around 12-1300rpms) might be too high for the rpms if that makes sense? As soon as I notice it start to jerk a little I give it gas and it stops. If I notice it and slow down, the truck downshifts and is normal again? It is annoying on a 40mph road that I drive on regularly, so either I go too slow or am speeding(not that I mind).

I suspect a bad Throttle position sensor. Has a flat spot in it sending bad information to the ECM.

thanks for the replies

I have the same problem on my 97, and have changed the cam sensor and vehicle speed sensor with no luck. I have tested the "sweep" of the throttle pedal, and it looked good. i am really leaning toward the under valve cover wiring. Mine acts up at 35 - 40 MPH with a slight pressure on the pedal, any more or less and it goes away. Lets keep this one going, until one of gets it fixed!

The reason that I am thinking TPS is it happens at exactly the same throttle setting. It's an electronic signal. I highly suspect a dead spot in the potentiometer.

have you changed your fluid lately??? just had the same problem on my 02 4x4 PSD X and i had the fluid changed and the tranny comp recalibrated seems to run fine now 30k miles on it btw

Oages, did you ever find a resolution to this problem? I'm experiencing the exact same symptoms on my 99 PSD.

steve.

Sorry Steveth, but I have not found a soultion to this problem yet. It does not seem to be as bad as it was a few weeks/months ago. If I find something, I will post it here. I just put over $700.00 into getting my 4x4 fixed (another post), so this one might have to wait a while as most of my driving is 25-30 mph or 75 on the highway. I am going to be due for a fluid change soon, so I will post if it made a difference or not. Happy Holidays

I agree with KWIKKORDEAD, the dead spot on the potentiometer makes a lot of sense

I have a '97 250 4x4 Ext. Cab. The truck wants to shift into 4th gear between 40 - 45 mph if I'm not laying into the thottle to much, in over drive. It will shift back and forth between 3rd and 4th when I'm cruising 40 - 45 mph in O/D. Are you driving in O/D? If so, try driving in over O/D off. See if that works. It may sound simple, but that's what it is on my truck. Transmission seems fine. Hope this helps.

I did try disabling O/D until I reach highway speeds and the symptoms go away. But I'm still concerned about what causes this issue - I can't imagine the truck behaved this way when new. However, I'm starting to think the transmission is fine which is a weight off my mind.

I can usually reproduce the problem quite easily now, I just apply light throttle in third gear. It feels like the truck shifts into O/D too early, the RPMs drop and it shifts down and back in again, sometimes a few times until it has enough speed to stay in O/D. If I mash on the throttle while in third, it goes into O/D fine.

I'll probably take it into Ford soon and see what they can do.

thanks for the good info here.

40-45 mph jerk
 

I'm expereincing the same. Very erratic feeling at this speed with neutral throttle. If I increase speed or take my foot off the throttle, the rough motion goes away. Does not appear to be hunting for a gear tho.
Kinda feels like the engine is "lost".
I guess you could start with the TPS, but was told they either worked or didn't.
Any other suggestions?

Gman17

I have a 99 f350 4x4 auto old style superchip at low setting. My truck shifts form 3rd to 4th between 45 and 50. It will jump back and forth a little when I apply light throttle between those shift speeds and in some cases seems to downshift inapropriately, but it's not as bad as what your getting. When I remove the chip it's not as bad. Maybe a programing thing???