John SCB

My odometer appears to be rolling 1/10 of a mile too fast...(with the stock wheels/tires). That means when the warranty is up at 36,000 miles, the car really only has 32,400 actual miles....not good for one of those borderline warranty issues.

Check out this link to a related law suit against Honda:

http://ktla.trb.com/news/ktla-hondao...ll=ktla-news-1

Has anyone had this happen with their Mustang?

neil07gt

how did you determine that? That's a 10% difference, and pretty significant if true.

DoctorQ

maybe the highway mile-markers were installed by someone driving a honda acura?

RRRoamer

My speedo is dead *** on. I haven't checked the odo, but given that it is electronic and the speedo is on, it BETTER be dead on as well. I REALLY don't think this is something Ford would play games with. It is way to easy to check the computer source code if there is a law suit to SHOW how the odo is talled vs the speedo (remember, they both get their pulse counts from the exact same place). If they did any "funny" math in there to speed up the odo, they would get OWNED by the class action lawsuit.

vsop

Actually there are laws on how the speedo must read. With the electronic ones that we now have its not a real issue, but with mechanical gears it was a big issue.

I know there are places that certify your speedo if you want.
Even with the electronic setup I know that in my 2000 when I put the gauge cluster in test mode and had it display the diital speedo gauge it read 2 mph slower then the analog speedo gauge

karman

What did you test the speedo with?

BLoG

it feels like my speedo reads high, but I have no basis for comparison. I just get that "is everyone else really going 85 also?" feeling.

mikes rx

I know that this happens during acceleration, because the gauge can not keep up with how fast the "numbers" are moving. The tach does the same thing, which is why when you install a shift light, it lights up "early" compared to what the tach reads.

Lennyb44

You are not alone.
I ask myself that question all the time.

steevr

My speedo reads 1-2 mph high. I've confirmed this with two different Garmin GPS's. The interesting thing is when the car is off or when I'm stopped at a light, the needle is not perfectly at 0, but rather just slightly above it. It's almost as if the person putting the speedo's together put the needle on slightly off.

I'm going to check the odo accuracy against the GPS's when the car comes out of storage in April. As long as I'm not racking up additional miles, I can live with the 1-2 mph over. Might save me a ticket some day (94mph in a 55 instead of 95 in a 55 )

karman

Mine tests the same as yours against GPS.

Chris728

Their was a problem like this with my sisters 04 chevy malibu a while ago. She was picking me up from a friends house and she noticed when she was driving her speedometer was reading a speed of half of the speed she was actually driving. Their were a lot of problems with that car though besides that. Up to 40 just to estimate. She ended up returning it as a lemon car and she got around $6,000 back. Take that chevy

2005GTDELUXE

Wow that's a HUGE problem they are facing. If I ever found out that I only had 32k and it was reading 36K I would flip out.

John SCB

My buddy's GPS showed .91 mile actually travelled for every mile shown on the odometer. I've also noticed the indicated speed is about 2mph faster on the speedo than on those road-side radar detector machines placed by the city police. I'll probably schedule a speedo/odo accuracy with my local AAA office.

GottaHaveIt

Well then mine has got to read 100 lower as I sure don't feel like I'm able to gallop fast enough !

G.T

when i first got my Garmin GPS, i noticed the GPS was always reading 10KM/h less than my speedo
later on while playing with my SCT XCal, i calculated the rev/mile ratio of my rear 18" tires, and set that with the tuner..
now my speedo reads the same as my GPS!!

my assumption is that all our Mustang Speedos are actually calibrated for the stock 17" rims. those getting the optional 18" rims or aftermarket upgrades have to recalibrate the speedo, as Ford forgot to do that

bradzpony

I've noticed the same thing with mine...that is, when stopped, the needle does not rest perfectly at zero.

pitpup

1. Are you running a CAI and Custom Tune?

Answer this question and we'll go from there...

John SCB

No. The car is completely factory stock.

RRRoamer

Two ways: timed miles at various speeds from 30 to 80 mph. All right on the money (less than 1/2 mph off at all speeds I tested) and with a portable gps (probably the most accurate. The most accurate data you can get out of a GPS unit is velocity data because it is a difference function which means any errors get subtracted out).