cchesser1990

my speedo has been reading low for a while, about 10-15 mph. any idea how i could fix this or cost involved?

Karl101

Has your rear end been changed?

wssix99

iTrader: (5)

Depending on the cause, the fix will be different.

In addition to the rear end, are your tires the stock size and/or have you changed the gauge face?

cchesser1990

i personally havent made any changes, but the previous owner could have.

wssix99

iTrader: (5)

OK... Are the gauge face, tires, and rear end stock?

cchesser1990

yes everything is stock as far as i know. could be some aftermarket gears in there but i have no idea.

Karl101

the faster you go, the more it's off?

blade2222

Also a4 or six speed?

cchesser1990

hard to tell if its off the faster i go, seems like it. its a m6.

Karl101

I think someone swapped gears

cchesser1990

if the stock gears are 3.42, and its reading low, do you think they went higher (3.73, 3.90) or lower? (3.23,2.73)

wssix99

iTrader: (5)

Do you have a portable GPS? They will have a very accurate speed rating on straight roads.

If you use the GPS, you can confirm if the speed off more the faster you go. If so, you can calculate what you have. If not, you can use the GPS to fix your gauge.

cchesser1990

i do have a gps so i can try that. but how would i fix it on my own? isnt it something that needs to be tuned?

wssix99

iTrader: (5)

If its a gear problem, yes. But you should confirm the problem with the GPS first. For a gauge face fix, its as easy as repositioning the needle on the face. (If the difference is constant at any speed.