I have a 90 IROC so Im assuming it has an electric speedo.
Anyways, My speedometer is horribly inaccurate
It floats and fluctuates around 0-30 mph all the time but it does slowly increase with the vehicle speeds
I have already checked the VSS for a good connection so that is out of the question.
I just replaced my ECM and am also having an idle problem when the car is in drive after coming to a stop the idle goes down to around 500 RPM's and sometimes actually dies.
I am not getting any codes for so I don't think the VSS is bad itself.
I did see that the VSS sends a signal to the IAC to control the Idle. Could these to things be related?
What besides the VSS could be bad in that system? Speedo gear stripped out??

 

anyone?

 

I had a similar problem with my tach. Turns out somebody had removed the indicator needle and put it back on in the wrong spot. Apparently they're extremely sensitive and weighted.

 

Im sure that would do it but probably isn't the case on my car.
It cluster doesn't look to be even touched and has everything has worked for the past two years

 

Are you sure it is electric? Not trying to sound like a smart a** but if it is mechanical it probably just needs lubed as mine did. Mine would do the same thing and mine is a mechanical unit.

 

I was thinking sticking cable to.

 

Yes it is electric. I have the VSS or Vehicle speed sensor

 

Mine looked untouched as well.
It worked fine for YOU for the past 2 years or.....

 

Yes for the past two years that I have owned the car it has worked perfectly