Hi there. I’m having a problem with my van. It’s a 1998 E350 with the 5.4 L. It’s getting a jerky emotion. Someone call it Trailer hitching. Under steady throttle or underpower on hills. It’s not super bad, but it is noticeable at sometimes worse than others, it’s a lot like when you have a bad coil kind of feels like a misfire. I’ve already replaced three of those, but they threw a code at that point. I’m not getting any code with this new symptom. I’m kind of leaning towards a bad oxygen sensor or possibly crank shaft position sensor. I’ve had symptoms like this other cars that pointed towards those two parts. But they’re not cheap and I don’t want to just throw parts at it. But again I’m not getting any code so I’m not suspecting another coil. Unless you can have a bad one without getting a code sometimes. My other thought was possibly a wiring issue but one important fact is it doesn’t seem to do this when I first start out in the morning. But as soon as it gets warm.It starts to happen right away.

 

You mentioned a lot of different maintenance, but nothing about the fuel filter, when was it last changed?

 

fuel filter I just did about two months ago. It’s been doing this for a while. That was one of the first things I tried since I didn’t get a code. And I want to mention it’s a lot like if a coil is bad kind of the same symptom, but again no code so I’m at a loss.

 

If you were getting a misfire, you should be getting a misfire code which leads me to believe the condition is fuel related.

This would be much easier to pin down if we were able to examine the data stream info, which requires a capable scan tool.
A malfunctioning oxygen sensor would show up there.

Can you try this,
Once it warms up to where it starts chugging, dump some cold water on to the crank sensor and see if it goes away for a while?,
I have had some similar problems with the multiple pin connector and moisture in that plug that is located under the battery , it plugs into the PCM.
Might be worth to check that connector..
Just need a 10 mm socket to loosen the plug.

 

Not a solution, but my '97 E150 5.4L has been doing that for years on hills or when it's really hot weather.
I found the quickest way to override the bucking is to TURN OFF THE OVERDRIVE, which drops a gear and smooths out the power and acceleration. Definitely not a fix or permanent solution but it gets me through the rough spots.

 

Sounds like transmission shudder to me...

I'm writing this from the point of view of newer vehicles (Ford Panther platform and E-Series) but it's basically the same transmission.
When is shudders, touch the brake pedal... enough to turn on the brake lights but not to actually brake. This unlocks the torque converter.

If that stops the shudder, I'd suggest a transmission "friction modifier". Like this:


This will likely get rants from the purists but it's worked for me on two Town Cars and one E-Series.

 

I tried this. Does alittle

 

I will try.
I did have a spare crankshaft sensor I put in. Seemed better today. Will know more tomorrow