Tach stoped working. Scaned PCM, came up with po342 & po343
witch is cam position sensor signal high and low. But the shift
light still works and the car still starts and drives fine......
Ocansionaly will be hard to start or not start

Would the cam sensor couse the tach not to work, but why
would it still start and the shift light still work ??????????

Shift light is spliced to the # 10 white wire from the pcm.
Help me out guys......

 

Somebody TTT

 

The tach is driven off the cam pos sensor, while the pcm (and the shiftlight wire) gets its reading from the crank pos sensor. The occasional hard start is because the motor does not know wether the cylinders are on the intake cycle or the exhaust cycle so it just picks one at random. When I had loose cam bolts and my cam started walking backwards, I only got the high error. Id pull the intake first and replace the sensor and see if that helps, if not, you might want to check to see if our cam bolts have loostened up.

 

Thanks man.

Also, would the cam sensor from a 98' work on a 02' ??
I have one of those...

 

While I cant be sure, I dont see why not, being as you dont have to specify a 98 compatible cam when you order a new cam shaft (the reluctor is the same throughout the years). I would lookup the part number for both years (gmpartsdirect or the like) just to make sure theyre the same.