Today I was driving on the freeway in my 1990 GTU. I suddenly notice I was going 80 mph on the speedometer but it felt like I was going maybe 65 mph. I was going to do a search but I didn't know what to search about my problem even in the FAQ didn't do much help. If somebody knows what I am talking about please give me some advice or at least point me to the right direction.

 

Speedo is within factory tolerance to be from 0 to 5MPH fast at 60 MPH.

And what the car felt like is hardly worth changing gears for. If you think it is wrong, get the car tested at a speedo shop.

 

Here's what you do- get a friend to trail you or drive next to you on the freeway.

Hold a constant 65mph for a mile or two.

Have your friend measure what speed his speedo reads.

Divide your 65mph by his result, multiply by 100, and you will find out what percent of the actual speed your speedometer is reading out at.

Make sense?

 

That only works if HIS speedometer is correct :p