I don't know what to say other than my tach reads exactly what IT WANTS to!!! It seems to be worse when the car is cold but it will still jump to a higher RPM seemingly whenever the fancy hits. Oh the only other bit of info I can think of... when it freaks, it's always to a higher RPM. I'm going to check out the level and make sure its correct tommrow, but if anyone has an idea HELP!!!!!!

 

Does your engine jump to higher rpms too or just the tach? I know if you have indiglow gauges the face for the tach tends to puff up and hinder the needle from moving freely. this may or may not help, but I tried.

 

Nope engine speed dosent change just the tach. Thanks tho

 

Cannot believe... more likely its doing what its told to do. Some where there is a short circuit injecting electrons by bucketfull. Each bucket gets u poor tacho shivering...
- test the sensor input
---ECU pin 53: 0V -or- 7-9V while ign on, engine stopped, front wheel is rotated
---Speed sensor connector pins a/b: merry go around on/off as front wheel is rotated

- Take out u instrument assy and try to find the reason for short. If u cannot find out, install a analog voltage gauge to the wirings coming from the sensor; if no problems there, the short circuit is in the i-assy.

try diggin more from here ...............↓↓↓

 

i have the exact same problem and i know its not the guage or guage cluster in mine.

 

Good to know I'm not seeing things!!!

 

ground check. you also might want to grind your starter.. this caused and fixed an inaccurate temp guage problem in 93 escort of mine. weird stuff.

 

Do you mean ground my starter???

 

He means grind it as in try to start while running. I also think he is high. lol

 

Also the solder points sometimes get loose on the pod. If you dont feel like messing with that buy a used cluster from a junk yard and change the tack only. I had something similar to this in my speedo, i tested everything and it seemed ok, but i changed it just to be sure. lo and behold problem gone.