Why is my tach needle jumping [Merged 9-9] tachometer jump

[Birt96gst]

While I'm driving my tach will start to jump around and my car will start jolt real bad
need help.

Would a CAS thats shorting out cause this or a cloged fuel filter or maybe just maye a cracked intake manifold?

need help fast need my car to get to work tomarrow

THANK YOU

 

[1gDSM4g63]

I though didn't have a noise filter with my new SMIM setup, but it's there and connected. Should I find a replacement or are there other situation that could be cause this problem?

 

[steve]

Many possible causes including a bad gauge but we covered the typical cases. A non-90 ECU and a missing or defective noise filter. Since your running a SIMM where is the coil pack located? It is a 90 versions, correct.

Has this always been going on or a new problem?

 

[1gDSM4g63]

I am running a 90' coil pack and ever since I got the SMIM and DSM Link this has been happening. I want to find the source of this problem, but I'm probably going to install the Dynatek ARC-2 CDI box a long with an aftermarket tachometer. So as long as this doesn't interfere with my ECU or tuning I'll just leave as is.