Help! Tachometer going berserk

[locutisj]

2006 Outback, the tachometer bounces all over the place whether it’s idling or not. Then it will drop to 0 and at the same time the AWD, AT Oil Temp and Sport lights come on. They go out when the tachometer starts moving again.
I reseated all the engine & transmission connectors I could find but no difference. Also not getting any codes from the OBD.
Any ideas?

 

[locutisj]

So I read somewhere that someone else was having a similar issue and they discovered if you press down on the connectors at the ECU it corrected the tachometer bouncing. I have the same results. Perhaps bad solder points on that connector, wires seem fine. I pulled the ECU out and opened it up and looked but didn’t see anything wrong. Anyone hear if there is a recall for this issue? I have searched but haven’t found any. Or anyone know where I could send my ECU for repairs?

 

[Ecmbuster]

A SSM2 scan tool will indicate if RPM's are hunting.
Test / clean all the battery ground cable connections at the engine block and the body.
Test / clean all the body to engine ground straps.
If the connections are tested - use a connection pin as a "drag test" and one solution I use is called Stabilant-22.
"STABILANT-22 is a patented polymer liquid that is non-conductive but in the presence of an electric field between the narrow gap of metal connectors, becomes conductive".
Or you have poor ground connections at the cluster / or defective tachometer.
Therefore, instead of sending components out for suspect repair, have a professional test the connections and component with an oscilloscope.