NON-MOPAR Automotive question......sorry guys but I need some advice.

[BATMAN]

Well I know what you are thinking, why ask a non mopar question here.....well I have no place else to go.  Here is the worst part, it is a Ford........Mustang.....SVT Cobra......I know what you are thinking but here me out.  There is no other message group out there with good advice.  It is a 97, I bought it a few years ago and the only thing wrong with it is the speedometer is off.  I think it is because it has 98 rims with kuhmo tires on it.  Does anybody know a way I can correct the speedometer?  Do I have to buy one of those expensive programers or something for it....I really don't want to put the money into that but I am sick of it adding so many miles to the car when I hardly drive it......plus my insurance company checks the mileage (limited to 5000 miles a year on that car) and I don't get to drive near that many because the odometer goes to fast to.  I had the cops use radar on it this is what it does.  Speedo says 25 actual speed is 19.  Speedo says 40 actual speed is 30.  Speedo says 100 actual speed is 80.  Any suggestions?

Thanks

[moparguy01]

You'll have to get a programmer designed to correct tire size changes. So yes, unfortunately you'll have to spend abit of money for it. but it'll be worth it to fix the problem.

[Charger1973]

The cops let you do 100? 

[BATMAN]

The cops let you do 100? 

No they only clocked me at the first two speeds I posted.  The time I was checking my higher speeds was up against one of those radar thingies that show you your speed when you drive and say slow down.....  When my speedo said 100 the radar thing said 80 something and was flashing red...... I have learned that if you are going to mess with those things drive by once normally check for cops who are reading the data in there car from the next block.  If nothing then go as fast as possible because they print off the numbers later on and laugh at some of the speeds.

[bee_fishy_6869]

Go to the stealership and get them to program in your new wheel size with the Ford scan tool. Changing wheel size can also mess up proper ABS operation. I'm sure they'll charge like an hour labor for the fix. I think it would take an extreme wheel size change to make such a difference like the speeds you mention however...

Could be a problem with your VSS?(veh speed sensor)

[bordin34]

Do you have any pics of you stang. I like the look of the 97 stangs. my dad has a 97 Convertible V6 Manual one with 32,000 original miles. He plans to keep it as long as he can and wont drive it unless the weather is perfect. They are great cars and it hasn't needed to be repaired once.