'07 Lariat 5.4 Triton. 77,000 miles.
In the 50mph range the tran feels like it's shifting in and out of OD. No noise but just a gentle bump.
Daughters '07 had same problem last year and had to replace torque converter.
Is this the best solution and will it last? Recently had fluid flush hoping this might correct issue but still there.
Thanks for any suggestions.
Tony in South Alabama

 

It's more likely a low grade misfire. With 77k it wouldn't hurt to replace the spark plugs.

 

I second that.