For about two years my tach allways showed real high(it would max out before it shifted). I went to the Chevy dealer and asked them what could cause this and they said the tach was controlled by the ECM and that was most likely what it needed.
The car set up not running for about a year and a half and now that the car is running again the tach stays maxed out. Does anyone have any ideas on what makes it do this or how to fix it?

 

No one has had this problem or has any ideas why the tach is acting this way?

 

Everyone has this problem or one similar.
I can tell you that the ECM does NOT control the tach. The tach gets its signal from the distributor not the ECM. It is either the tach filter in the distributor or the ach itself that has gone bad.

 

What about the tach filter, can I get another one? Where in the distributor is it?

 

The tach filter is under the rotor, it is a large silver condenser. you can buy just the filter or you can get it with the connector for the module and all. Most any parts store should carry it.