Hi I have a 2000 Ram 1500 and I am having some serious problems ! It's albeit hard to describe by my best way to put this is that the RPMs fluctuate creating a "whammying" sound with the exhaust. This happens crusing at anyspeed from 35 to 70 mph. Sometimes it will surge while idling from 500 to 1800 rpms. It is enough to make the vehicle move at a decent rate of speed if not applying the brake. The speedo needle also fluctuates from 0 to 100 violently, sometimes just staying at 0mph despite actually going 60 down the highway. For some odd reason, the ABS and emergency "BRAKE" light are on along with the check engine light. When the ABS and BRAKE lights are on, the brakes work fine and the parking break is disengaged. Any help would be greatly appreciated. Tommrow I will check the code of the check engine light but it always just comes up with a O2 Sensor message. I have replaced the O2 sensor and the problem persists. This is my only ride and I need it to get to work and school. Any help is great. I need this fixed !

Thanks alot, Jon V


p.s. Gas mpg has takeN a huge turn for the worse with this problem

 

the brake and abs lights along with the speedometer are more than likely due to a bad rear wheel speed sensor.
the rpm fluctuations are more than likely due to a bad throttle position sensor. the haynes manual tells how to test it with a multimeter.
surging at idle can be caused by a bad idle air control valve, bad automatic shutdown relay, bad camshaft position sensor (that one throws a CEL) or a malfunctioning fuel pump.

 

Thanks I'm going check it out today.

 

there is a TSB (tech service bulletin) for this problem. go get a flash for this at your dealer. start with this first before you diagnose sensor problems.

 

What was/is the code(s)? And which o2 sensor was replaced?

 

The problem was a sensor on top of the pumpkin on the rear axle. thanks for all your help.. jon

 

cool. its nice when its something thats easy to change.