Ok well ever since I bought my 98 CSVT I have suspected that the speedo was off by a bit because it said I was going faster than it felt. Recently I confirmed it because I bought a GPS that also tracks my MPH and my speedo seems to be off between 6-7 MPH everywhere. I thought that was kinda weird since it is the same amount off no matter how fast I was going so I am kinda confused as to what it could be that is causing that. The only thing I can think off is perhaps the need skipped one of the teeth that it sits in, but I dunno.

Any other suggestions?
Thanks guys

2001 Volvo S40-Perrin MBC@ 11psi, EST intake, 35% tint, still slow