Expy Shudder once in over drive

[Delerious]

I have a 2005 XLT that has a shudder once it shifts into the highest gear and continues to shudder when it accellerates. Had all the fluids flushed and changed (ie engine, tranny and diff) as well as a fuel treatment and filter. It first called out a misfire on number one so I changed the spark plug, which was bad, but didn't fix the problem. Swapped coils from 1 to another cylinder, no joy. The engine does seem to run better after the fluid flush and filter changes but we still have the shudder. Any help would be greatly appreciated.

Nick

 

[phoenix101703]

I'm with delerious here. After around 45-50 mph when I try to accelerate (slowly so it stays in overdrive) I get the "shudders" too. So now that makes two of us. If anyone has any suggestions or ideas that'd be awesome!!!

P.S. I have an '06 XLT

 

[ExpyKurt]

Mine is doing the same, i am having the plugs changed this weekend. We will see if this fixes the issue. Also, might have the COPs looked at. I had to have cop 1 & 7 replaced, fixed the problem for a little while. Could be a combination of both.

2005 xlt 5.4l

I'll post if this fixes the problem

Edit: 90k miles on her

 

[ExpyKurt]

Just got the truck back from getting the plugs changed, and the truck runs great! Fixed my problem of the shuddering at high speeds, and maintaining speed up hills. No misfires, only hesitation is between shift points. but nothing extreme.

I don't know if this will help your situation, but at least it's an idea.

 

[Delerious]

How do you see if the coils are good or do you just swap with another cylinder and hope the computer calls it bad?