Installed a set of Rick's 4.56s and the yellow box in my '03 and the speedo still reads too fast. At 40mph I am actually doing 35mph, at 70mph/65mph, and at 90mph/82mph. It seems that above 75mph the error increases to 8mph over and holds steady. This is with all switches on, so no more correction is possible. Right? Actual speed was verified with GPS.

 

You installed smething wrong or your yellow box isn't working.

 

you are not supposed to switch all of them on. try this...

1- off
2 - off
3 - on
4 - off
5 - off
6 - on
7 - on
8 - on

 

^^^
Hoa, whats the correct setting for 4.57?

 

Make sure you have a good ground as well.