LTFT different at lower and higher MPH and RPM

[fumi]

Is there a certain speed I need to maintain to set my LTFT?
At 55mph my LTFT's are .78 and -1.56
At 70mph LTFT are -2.56 and -3.12.
Do I stay or readjust.

[rmck490]

Speed doesn't matter as long as you are at a steady cruise speed in the 1800 to 2200 RPM range.

Likely the difference you are seeing is at 55 MPH you are less than 1800 RPMs. In my truck, I have to go 61-63 MPH to get over 1800.

Your 70 MPH readings are probably in the correct range so use those results to adjust your LTFT. Looks like a +2 adjustment will get you where you need to be.

[2sscamaro]

Is there a certain speed I need to maintain to set my LTFT?
At 55mph my LTFT's are .78 and -1.56
At 70mph LTFT are -2.56 and -3.12.
Do I stay or readjust.

Your trims are good. Don't be chasing them. The will always be slightly different from day to day in different temps and different speeds.