Have a 2004 lariat screw with 178,000 miles. Rebuilt ford tranny put in at 118,000 miles. Getting a fish bite like shudder only when in OD between 40 and 50 mph. Never get it with OD off. Assumed misfire. After plugs and COPS replaced . Throttle body cleaned. My gas mileage has improved but still has shudder. Added shudder fix with no improvement. Seems to point towards torque converter. Wanted to know if you folks have been through this and have any suggestions. Have seen a video pulling the valve body to fix torque shudder issues. Any suggestions??

 

It still could be a misfire, especially if you used non-Motorcraft plugs and coils. Delphi and Denso coils are okay, but other brands are a crapshoot. You also need to use a small amount of dielectric grease in the coil boots, NOT on the contact springs.

 

Classic symptom of a "low-grade misfire".

 

I would also try some Techron in the gas. Could be dirty injectors.

 

Guess I should have also added that they were all motorcraft parts and no codes.. any brand of injector cleaner that might be better than others?

 

The lack of codes is not determinative. Neither are "new parts".

Use your scan tool and look at the Mode $06 misfire data to see if any cylinder data shows misfire counts when the shuddering occurs.

 

Techron is the best, and approved by Ford.

 

Very common on these trucks. Saw a video covering this and the guy installed Accel Supercoils instead of the OEM. Seemed to fix it. I don't personally have experience with them but might try that route when it's time to replace the coils.

 

I have also heard that Accel coils are no good on these trucks.

 

And if you run out of coils and plugs, try changing the transmission fluid out. 178,000 miles less 118,000 miles is still 60,000 miles.