Pathfinder tachometer question

[Crazytalk21]

1987 PathfinderI have a base model pathfinder and someone replaced the dash cluster with one that had a tach and a clock on it cuz it looked better. Everything works good the only thing is the tach doesn't work properly it slightly jumps up every now and then while the car is running but thats it. So i was wondering if it was possible to fix it to get it to work? Any help would be greatly appericatied.
Modified by Crazytalk21 at 8:45 PM 12/24/2007

[driftingmy240sx]

so we understand the complaint. the tach works but every so often the needle jumps. how high does it jump a few rpm or does is move a few 1000 rpm? the tach recieves its signal from the ecm as to the rpm of the engine. i have seen clusters go bad and cause wild tach and speedo readings. it could even be a defect in the crank sensor system.

[Crazytalk21]

It jumps only a few rpm and when u rev it up it on ocassions it may jump close to 1500 but it seldom does, sorry about that leave that out.

[driftingmy240sx]

sounds like the tach or the wire from the ecm to tach is bad

[Crazytalk21]

Ok so i checked out the tach to day and noticed that it only jumps when the lights are on or the turn signal is on. So i took it out and found out it does work properly, just faulty wiring.
Modified by Crazytalk21 at 1:41 PM 1/18/2008