tach gone wild

[yellowdub]

whats wrong with my tach ever since i got the truck some times it works fine and others it seems slow and sluggish also rpms reads what seems to be half of what it really is like if im at idle whitch is 650 rpm it will be at 200 rpm and at cruising speed i know im at 2000 rpm and its at 3000 rpm.
WHAT SHOULD A 06 2WD AUTO 4SP W/OVERDRIVE RPM BE AT 60 MPH IM AT 2000 RPM. IS THAT RIGHT.

[seagoo]

If you find out let me know, please. I have posted a question on this before, but no answers. Mine only does it at idle. Drops down, then back up, and will correct itself as soon as the gas is hit. I think it reads the RPMs off the camshaft or crankshaft position sensors, not sure which one. I didn't get an answer to that question either. My truck is a 2006. I don't want to drop $50 on sensors and that no be my problem. It seems to do it when the grid heater cycles too.

[tclappcummins]

well I will let you guys know the CPS ( cam position sensor) is not the problem! I have the same thing and I dont know what's causing it. I replaced both CPS and still have the problem.... the only way I know what RPM's I am running is thru my edge

[dontneedtostroke]

my does the same thing and its happened to a couple of my buddies and alot of other people i know. it has something to do with the wiring in the cluster and ive heard that the only fix is to get a new cluster. but before you go all crazy spendin all that money check all your wiring connections.

ive checked everything on mine and i know its gotta be something with the cluster itself, faulty gauge or whatever but everything is good

[(mosquitocontrol)]

Mine drops at idle and if I press the trip meter reset kind of hard the tach will jump back to where it is supposed to be.

[yellowdub]

i did the gauge test and its in the cluster im going to say screw it im not going to worry about it for now it runs fine and im not racing it