ok, im new here and i have a problem i really cant figure out. my abs light will come on and the speedo either doesnt move (stays on 0) or jumps around and doesnt want to shift so the rpm's red line. i have a 2000 ls blazer 4.3 v6 4x4.

 

Is this 2 problems or 1 that you think is related to each other? Have you had your codes read? Something like this should throw you a fault code or three. Some auto parts stores will read them for free if you don't have a scan tool that will read OBD2 codes. I'm not familiar with a 2000 model, but tjat thing will put a code for just about anything wrong.

 

This sounds like a bad vehicle speed sensor. Or possibly a damaged plug/harness to the sensor. This sensor is located on the transfer case.

When the vehicle speed sensor is not functioning correctly your transmission will go into limp mode and stay in second gear because not knowing your speed in relation to your rpm's it won't know when to shift. It should not be driven like this past getting it to wherever you plan to fix it or you risk damage to your engine due to the high RPM's. If you absolutely must drive it somewhere to get it fixed then keep the speeds low and you will not red line and toast your engine.

The ABS code comes in because the ABS speed sensors in your front wheels are not receiving a proper signal corresponding to the readings that the computer is getting from the VSS. When this happens the computer throws an ABS code and the system is shut down for safety reasons.

If you fix the bad harness/VSS sensor then everything should return to normal.

 

thanks for all the info. i took it to get looked at alittle over a week ago, and when i told them what it was doing (it comes and goes) they just kind of looked at me with a crazy look. they said one of my o2 sensors was bad and needed a new evap canister. i changed the o2 sensors and just got the evap canister yesterday. i will have the speed sensor cheched as well.