2004 Freestar Limited with 4.2L, about 104K miles.

It has a very intermittant but very noticable transmission jerk at cruise speed (50-65 mph). Feels like the transmission disengages to shift/downshift, then re-engages. Fluid is OK. It had some kind of transmission recall work done a couple years ago (torque converter?). This is my mother-in-law's car. She bought it new and has taken very good care of it. Any ideas what could cause this?

What's been done:
-TQ converter recall/repair
-Coil replaced, new plugs, etc.
-Alternator replaced (2 yrs ago)
-Fuel filter replaced about a year ago
-Regular routine scheduled maintenance all it's life (fluids, filters, etc)

 

Based on the symptoms described in your other post and this one, I would try replacing the Cam Position Sensor. It's about a $15 part and easy to replace.

 

Since this is the thread I started I'll try to stay here...instead of piggy-backing on the other threads I have been posting on.

Her car is still experiencing the same symtoms and even stalled out on the road recently, but restarted and she drove it home. I convinced myself it had to be transmission related, but no longer have any confidence in my diagnostic skills with this vehicle.

She's never mentioned any noises like are described for cam synchronizer failures. I'll try the sensor replacement and see if it helps, as you say it's a cheap part. It's not fun being on the other side of the state and trying to trouble shoot...

 

It could be the cam synchronizer itself. My van stalled about 5 different times when mine was acting up on a trip to AZ. I just posted in another post the replacement procedure that I did when I replaced mine. They are as follows:

It's actually not that difficult. It took me about 2 hours to do mine start to finish. The new cardone unit (part #84-S2601) was $10 more than a rebuilt unit and it includes the cam position sensor.

1. Drain the cooling system down
2. Remove serpentine belt out of the way.
3. Unbolt the P/S pump and move over out of the way.
4. Remove coolant tube that Ford put just in the way of removing the cam synchronizer.
5. Remove the cam position sensor.
mark the cam synchronizer housing and the engine block with your favorite color sharpie.
6. Put a mark on the new cam synchronizer in the same place as the old one.
7. Put the new unit in so that the mark on the new unit lines up with the mark on the block (no need for the sensor install tool with the marks).
8. Tighten the new unit down and install the new sensor.
9. You may need to put a new O-Ring gasket on the coolant tube, I just used some copper-plus silicone and reused the old o-ring.
10. Put everything back together and top your cooling system off.

Take your time, you should be fine.

 

UCS,

I see you have pretty much the same vehicle as I'm dealing with.

Had you experienced any [related] issues prior to the trip with the stalls? Was there any rhyme or pattern associated with your stall experience on that trip? I'm sure I can do the part replacement you described (thanks for the description). I'm just wary of throwing too many parts... already replaced the ignition coil for this issue.

 

That particular trip was uneventful from NY down to Portales, NM. There it stalled a couple of times when turning around at my Sons house. I was like Hummm...weird. The van was loaded to the gills and stuff loaded on the rood. Was like a white brick rolling in the wind. Then we drove to our other house in Arizona and the van ran fine. Engine ran a few hundred miles between 3,000-3,500 RPMs from Las Cruse, NM into AZ due to the climb and wind resistance. Once at our place in AZ., the van started to experience the harsh jerks. I also replaced the alternator at the same time as it was also bad. It was only putting out about 12.3vdc and running hotter than heck, you could smell the winding cooking. The shaft on my cam positioner was bad. Was very hard to turn by hand when I had it out. and you could hear and feel the bearing were dry.

 

"I was like Hummm...weird."

Exactly how my MIL and I are thinking. I think I'll just order the combo shaft/sensor and replace it and see how that works. Not too expensive or difficult to do. Your other solution (re: brake sensor) saved me/her a bundle, and it seems to be a common problem in these engines...can't hurt.

 

Nope, can't hurt for the cost and your time to replace it. And the "BIRD CHIRP" symptom that normally goes with a failing cam synchro didn't really start until the day that I replaced mine and that was just an occasional chirp, so in saying that, you won't always get that particular symptom.

 

...went through all her repair receipts this afternoon. It's at about 112K miles now.

The cam position sensor, and cam synchronizer housing (what the shop work order states) were both replaced by a Ford dealer shop at about 75K miles. Would they go bad so quick (about 30K after replacement)?

 

It could. Just changed mine for the same symptoms. Jerking at light throttle "cruising speed" and random stalling. Mine wouldn't accelerate through the full rpm range sometimes too. I didn't hear a squeak unless it was very humid out. But my cam synchro bushings were shot. Once taken out it just flops around. It wasn't hard to replace, a shop should only charge a couple hours labor. As long as it goes back in how the old one came out there is no special anything required. It's like a distributor. Mark where the old base sat and where the rotor points. I took pictures of it too.