Speedometer and gas gauge are giving false readings!

buy a new speedometer at a junk yard. stick it in the dash

solution is to take apart the speedometer and change interior fuse

I, feel sorry for you, after reading your problem, but don't worry you visit the Reliable-Store they will help you for sure.
1988 2002 Isuzu Holden Rodeo TF R7 R9 Workshop Repair Service Manual...

Are all fuses and relays ok? Also a loose ground wire can give u alot of trouble

Hello: To correct this condition you will have to replace the cluster. After replacement the mileage and engine hours will have to be reset then the cluster will have to be programmed to your truck.

GM had problems with a part inside the instrument cluster ,called a stepper motor .2003 to 2006 This stepper motor controls the gauge needle .
How to repair GM Instrument Cluster Speedometer Gauge Stepper

Take out the speedometer gear and hook it to a cordless dril (electric drills might spin it too fast). Turn the ignition to the "on" position, but do not start the car. Have someone watch the speedometer from inside the vehicle as you spin it.

If the speedometer gauge works and stays constant, then you know your problem is with the drive gear or the worm gear on the inside of the transmission.

If it doesn't work, then you know that there is an electrical issue with the speed sensor circuit or something in the gauge cluster is broken.

I had a problem in my Explorer with the speedometer gauge jumping around (and that really messes with teh 4WD system). I chased it for a couple of weeks only to find out that the nut that secures the worm gear for the speedometer in the transmission was loose and devoured the drive gear.

You need to replace the speedometer gear that drives the sensor.

You need to replace the speedometer gear in the transmission. see http://www.myisuzuparts.com/index.php

You need to replace the speedometer gear that drives the sensor.