ok I've had this problem for a while now

basically the tach jumps around, it points at 2k when i'm really idleing at 1k, points to 5k when i'm driving at 3k etc... it would do this 7 out of 10 times I drive the car..

at first i thought it'd be bad grounding, but every time i add a ground wire the tach will settle, and would be fine for a week or two, and it start jumping/overreving again. so far I have 5 grounds including the stock one, i'm using 2 and 4 gauge wire....

so is my cluster messed or is there another problem at hand??

 

stock tach?
if not where is the aftermarket one plugged in?
Jason
JT-Imports
Yokohama Japan

 

i have a stock tach and am having the same problem

 

yeah its the stock tach, its really annoying!

my mods are if it matters

dp, mp, cb, smic, intake, pettit ecu, bov
93 w/100k kms

 

oh if I let the car idle for around ~ 10 mins it will eventually settle. this works 5 out of 10 tries, if I idle for 1~2min and drive it to warm it up, the tach jumps... sooo..........

anyone??

 

dont know if its related but tach was jumping around randomly right before my alternator went out.

 

..posted this a while back on another list as i have it as well and the concensus was a bad instrument gauge cluster...