while I was driving today, the rpm needle was bouncing all the way up to 8k, and i was doing like.. 5mph? When I shut the car down, it was still bouncing a bit until it finally settled. Do I need a new instrument cluster?

Also,
Will this effect my ecu readings, or fuel output? I hope the computer isnt confused.

TIA!

 

The crazy tachometer is pretty common. All cases I've heard of, the tachometer itself was the problem and it doesn't affect any other part of the car. The usual cause is bad solder joints on the printed circuit "film".

If your car is running fine, it's nothing serious. If it were something like a bad crank angle sensor, or related wiring the car would have serious, and very noticeable running problems.

Search for "bad tach" or something similar, it's been covered before more in depth.

 

The needle actually went past redline and stayed there for like 10seconds and i was rolling at about 10mph. scared the feces outta me

 

also when it was bouncing that high, the rev limit buzzer didnt go off.

unless my PFC disables that?

but it was almost like 6k was 0rpm