KIA INSTRUMENT CLUSTER GAUGES TACHOMETER NOT WORKING

When Starting Up It Reads 0 While Running, Then It Bounce Up In Down Between 0 And Normal. Once Warmed Up It Operates Normal. After Running...

How Would I Go About Fixing My Tachometer? I Know I Need To Replace The Upstream On The Catalytic Converter And A Speed Sensor Also. But...

Tachometer Does Not Work Properly And When It Does The Car Runs Rough, When I Go Somewhere It Goes Fine But Once I Shut It Off It Takes...