ok there is alot of things this could be, i just not totally sure wanted to see if anyone else has had this problem

ok i hav a 93 civic cx hb, when i got the car it had an autometer tach that didnt work that great, it jumped all over the place and was never really right. so what i did was cut the wire to it wrap it in elec tape and tuck it in the dash. after that i got a DX cluster that has a factory tach hoping that would fix my problem, well that tach works better but it still once you hit 3g it likes to jump from 3 to 4500 and back till the motor gets above 4 then it is fine till about 8500 and then it jumps some more right before i shift.

the car has alot of extra wiring under the dash such as radio stuff, fog light wiring but it looks to me like he ran the tach wiring through the main harness that runs next to the column, i thought i fixed the problem when i saw he has got the power for the tach light from the fuse for the dash so i disconnected that and it now does it less but i am looking to try to get rid of it all together.

any help would be great, a ground is the normal answer i get and i hav also swapped motors so i dont think it is anything with the engine seeing as it did it before and after the swap

let me know what you think

 

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