So- a few weeks ago, my truck died. My buddies Snap on scanner said the crank sensor was bad. I replaced it. The old one looked a little worse for the wear on the end. The truck runs again, but no more than 20 minutes of run time, and the CEL came on, and the tach went to 0 and back (a few times actually). Today, the CEL light is off (I cleared the code) but the check gauges light is on, the oil pressure gauge reads 0, and the voltmeter reads low.
I have searched on here about the tach problem and read nearly every thread that was remotely relevant to my problem, but I still have some questions. Once or twice I saw mention of the tone ring possibly coming loose. Could this be my problem? I will pull the crank sensor back out and check it for damage. If the tone ring is loose, how does a person go about repairing this?

 

oh- it is a 24 valve truck.

 

u have to pull the oil pan...the tone ring has known to come loose and or break apart. sometimes the crank sensor is installed too deeply and will hit the tone ring...do not overtighten the retaining bolt.

 

I thought the tach reading came from the cam sensor?

 

On the later 24v, it used the cam sensor. Prior to that it was the Crank.