speedo off

[98outbackpdx]

on my 98 BK the speedo is off by -2mph and i am not sure what is causing it. i do have the correct tires, 205-70-15, i just had the head gaskets done, by a Subaru tech, could he have bumped something? no check engine light is on. i noticed it a few days ago after i got the car back, i went by one of those speed radar things that tell you your speed, and it was -2mph off. also the millage i am getting is not correct, it is 72 miles from Gresham Oregon to The Dalles Oregon and it said on my trip odo 69 miles, so i know something is off. any insight would be appricated. thanks

[Grafton]

it's just one of those little annoyances that you'll have to live with, mine was off about the same amount

[jey]

You do not have the correct tire size. The BK Legacy tire size should be closer to 24.9" overall diameter. 205/70/15 is more like 26.3"

The 98 Outback is supposed to be 205/75/15, which is even bigger than that.

[lozanoa11]

Most speedos are off. I have heard that jeep would set there speedo's off to counter act the very likely event of the owner buying bigger tires.
Edit: to answer your question, there is nothing he could have done to make your speedo off.

[Huffer]

The radar units have an error factor also. So does your speedo. Every speedo does. Not even GPS is 100% accurate as the signals are bouncing back and forth.

If your speedo was 5mph+ off, that would be a concern. But 2mph? Someone's got some fairly extreme OCD! :smt005

[02legacygt]

yeah my speedos off as well, thats becuase i went up in tire size though! :lol:

[98outbackpdx]

i know i have posted about the speedo being off, but i think it is more than that. it is really weird, i will have the cruse control set, speedo stays the same and so do the rpms on the cluster, but i know that the car is speeding up and slowing down. i am not touching the brake or gas i am sure of it. take my shoes off and move my feet from the pettles.
no check engine lights on.
the day i got the car, my mom was ahead of me, she had the cruse in her Astro van set and the cruse in my car set at the same speed, but she kept getting ahead of me. same thing happened with my bros '07 Impreza, my car would not stay at a consistent speed, and he would get ahead and then i would be caught up, then farther back, kind of like a cat and mouse type of thing.
i don't know if this makes any sense, this car has had problems since day one of ownership, even got it from a Subaru dealer.
i know something is off and it is really starting to piss me off, and if one more thing breaks on i am gonna just trade it in and get a kia.
i do not have the money to get it on a dyno or something like that, and where i live we don't have to do emissions testing, (lot of chopped of exhausts) so i don't have a rolling road kind of thing (also no safety inspections, Oregon doesn't use salt.) i just had to fork out $150 for a new mirror because someone hit it with a bike, and didn't leave a note, so i don't have the extra money.
anyone have a similar problem, let me know. i have not gotten a radar detector for this yet, and i tend to go over the speed limit. lead foot runs in the family. so i got the led foot gene.
any help would be appricated

[Huffer]

Merged threads, you're not starting a new one on my watch.

As for your problem - if the car speeds up and down WITHOUT the RPMS climbing/falling then... that makes no sense.

I do know for a fact that many cruise systems are inaccurate at maintaining a given speed over certain types of terrain - flat freeways are the best for cruise, long curvy country roads aren't. My father in law has a 97 Astro and they are NOTORIOUS for being inaccurate at controlling cruise on anything but buttery highway. The 07 Impreza should be a lot better. My guess is that your 97 is just not that good at maintaining cruise. You could try cleaning out the throttle body and seafoaming the vacuum pipes to see if that helps your throttle response, which might help the car to make cruise adjustments better.

[1-3-2-4]

I've noticed the faster you go the more off it is.. however driving at say 20 or 40 mph it's pretty much correct but at 80+ it can be as much as 5-7 MPH off as in your speed is showing faster then what you are really going.

[98outbackpdx]

sorry about the 2 different threads, could not remember where the CC one was at, lot on my plate right now. which car did you say to clean the throttle body the astro or the outback, both are a 1998. probably about 10k miles the maf sensor on astro was replaced, they supposedly cleaned everything out, but idk it is was done the same dealership chain i got my car from and got f-ed over on my car, so idk what was actually done except the maf sensor.

[98outbackpdx]

and not even 3k miles ago the HG's were none on the outback by a subaru tech.