Tach guage dying?

[ruzztec]

What has seemed to become more frequent, my tach needle will jump between a 500rpm range 1500 -2000 usually and then sort it self out and stay at 2000. then do it again later. Yesterday I was going 20 mph and the tach went to zero. I freaked out thinkin my engine was dead. Nope just the gauge. Now iv never messed with the tach but i presume i should check around the tranny? or does that cable just control the speedo? Any clues?

 

[majdi]

check the crank position sensor i think the computer uses signal from the CPS to get the rpm

 

[pugsy]

My tach is stuck at 3500 RPM. I though the tach was run from the ignition coil (or at least on my old car it was like that)

 

[ruzztec]

what exactly would i check for? i mean would a loose connection or faulty cps not throw a check engine light?