Baby Ollie
Pokemon Master
First off, let me say that my car is a completely stock 2000 GS. Stock LS Mesh wheels, good tread on the tires, nothing that should distort the speedometer reading. I am aware that most cars will read a few MPH above your actual speed, and a few MPH discrepancy wouldn't bother me at all. However, my GPS consistently shows that my speedometer is reading 9-10MPH slower that the actual speed of my car (assuming the GPS is correct). The discrepancy really kicks in at the 65-83 MPH mark, and then returns to mostly accurate readings. I've included a table to give you an idea of what I'm dealing with. The speed on the right is my speedometer, and the speed on the left is my GPS. The deviation is listed on the far left.
Speedometer........GPS................Deviation
50.............................48.................+2
55.............................52.................+3
60.............................55/56............+4/5
65.............................59/60............+5/6
70.............................63/64............+6/7
75.............................58/59............+6/7
80.............................72/73............+7/8
85.............................82.................+3
Anyone know why I would have the most issues at the 65-80 MPH mark? I have tested the GPS in my girlfriends car (2002 Focus) which is almost always spot-on regardless of speed, and my dad's car (2010 Legacy) which is constant 2-3MPH deviation regardless of speed.
I do a lot of driving over Snoqualmie Pass (I-90) and the speed limit most of the way is 70MPH. It's really annoying to not feel like I can trust my speedometer to get my true speed. I tend to error on the side of caution though, since as a 22 year old male, I cannot afford moving violations on my record.
I'm praying that someone here will have an easy, simple fix. I am mostly car illiterate, and don't feel like shelling over a few hundred bucks to a mechanic for something like this.
Thanks for any and all help!
Speedometer........GPS................Deviation
50.............................48.................+2
55.............................52.................+3
60.............................55/56............+4/5
65.............................59/60............+5/6
70.............................63/64............+6/7
75.............................58/59............+6/7
80.............................72/73............+7/8
85.............................82.................+3
Anyone know why I would have the most issues at the 65-80 MPH mark? I have tested the GPS in my girlfriends car (2002 Focus) which is almost always spot-on regardless of speed, and my dad's car (2010 Legacy) which is constant 2-3MPH deviation regardless of speed.
I do a lot of driving over Snoqualmie Pass (I-90) and the speed limit most of the way is 70MPH. It's really annoying to not feel like I can trust my speedometer to get my true speed. I tend to error on the side of caution though, since as a 22 year old male, I cannot afford moving violations on my record.
I'm praying that someone here will have an easy, simple fix. I am mostly car illiterate, and don't feel like shelling over a few hundred bucks to a mechanic for something like this.
Thanks for any and all help!