I have a 2006 Dodge Ram 1500 5.7 V8. The check gauges light came on and she lost some power, didn't cut off but would not move. I turned her off and restarted and she drove fine. What could have caused this besides the normal check all your fluids? I did replace the battery within the last 4-6 months. And my RPM gauge has been acting weird....not going high but not registering the RPM's a lot of times.

 

Did the CEL light come on at all? Take it buy a auto parts store like Autozone and let them scan the truck for codes. At this point you do not have enough info to direct you or us.

 

The CEL light has been on but when I had the guys at Autozone run it they said it was just the speed control sensor and nothing major so I haven't replaced that yet. When I was out today the RPM gauge isn't working at all now or should I say it barely goes above 0. Not sure if the gauge light and that have anything to do with one another. Bought the Haynes book today and can't find anything about either issue.

 

Haynes manuals suck. Click on the links in the signature for your Service Manual for your truck. You will find it MUCH more useful and educational.

Here is something from page 1869 you might find interesting

OPERATION

The tachometer gives an indication to the vehicle operator of the engine speed. This gauge is controlled by the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster
from the Powertrain Control Module (PCM) on vehicles with a gasoline engine, or from the Engine Control Module (ECM) on vehicles equipped with a diesel engine over the Controller Area Network (CAN) data bus.

The tachometer is an air core magnetic unit that receives battery current on the instrument cluster electronic circuitboard through the fused ignition switch output (run-start) circuit whenever the ignition switch is in the On or Start positions. The cluster is programmed to move the gauge needle back to the low end of the scale after the ignition switch is turned to the Off position. The instrument cluster circuitry controls the gauge needle position and provides the following features:

² Engine Speed Message - Each time the cluster receives an engine speed message from the PCM or ECM it will calculate the correct engine speed reading and position the gauge needle at that relative engine speed position on the gauge scale. The cluster will receive a new engine speed message and reposition the gauge pointer accordingly about every 88 milliseconds. The gauge needle will continually be repositioned at the relative engine speed position on the gauge scale until the engine stops running, or until the ignition switch is turned to the Off position, whichever occurs first.

² Communication Error - If the cluster fails to receive an engine speed message, it will hold the gauge needle at the last indication for about three seconds, or until the ignition switch is turned to the Off position, whichever
occurs first. After three seconds, the gauge needle will return to the left end of the gauge scale.

² Actuator Test - Each time the cluster is put through the actuator test, the tachometer needle will be swept to several calibration points on the gauge scale in a prescribed sequence in order to confirm the functionality of the gauge and the cluster control circuitry. On vehicles with a gasoline engine, the PCM continually monitors the crankshaft position sensor to determine the
engine speed. On vehicles with a diesel engine, the ECM continually monitors the engine speed sensor to determine the engine speed. The PCM or ECM then sends the proper engine speed messages to the instrument cluster.
For further diagnosis of the tachometer or the instrument cluster circuitry that controls the gauge, (Refer to 8 - ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING).

 

I would start by getting any codes pulled. Makes it easier to diagnose, and prevents throwing parts at the problem. If you are able to pull a code checkout ALLDATAdiy.com for complete factory diagnostics.