I have been having an intermittent problem with my tachometer dieing. The check engine light will turn on and after a while the tach will return to normal. After a few cold starts, the light will go out, so the code must be clearing periodically. The truck runs, and the speedo, gauges, charging system, A/C, etc all work fine with or without the tach. Sometimes it does it on a hot start, tonight it did it just driving down the road. Power with or without tach seems fine. Mileage is great, I am getting 23 mpg in mixed driving. I haven't pulled any connections apart - yet. I am thinking it is the Crank position sensor, as I have always had a lumpy idle, especially when hot. Looking for some ideas, before I do anything drastic.

 

been a while since i messed with 2nd gen but i think if the tach stops working the cam sensor under the vp44.

 

crank position sensor, crank position sensor, crank position sensor. its a 10 minute job.

 

I've diagnosed a couple VP44 equipped trucks with intermittent tach problems. Crank sensors were the culprit.

 

99's have a crank sensor, 2000-up dont, the crank sensor controls the tach.

 

My truck had the CPS changed at 93K. The tacometer was eractic as well.

In service Date for my truck was Dec 99.

Dave

 

Thanks for the info. It seems the Crank Position sensor is worth the effort to just go fix. My ABS speed sensor died about 20K ago, so I am not surprised that this died at 118K. Now to find a cheap source.

 

It's not a ten minute job, You need to remove the starter to get to the Crankshaft Position sensor on the 99' it'll take about a hour or so.

 

Mike Perez is correct. When the tach would cut out in my '99 i would loose some power. I replaced the cps a couple of years ago, it was about $75.00 at NAPA.
Worked fine since then.