here's a tuffy

so i was driving my mom's 03 trailblazer and i was doing about 50 and i was about to go down a hill so i put it in neutral hoping that the rpms would drop, they didnt, they stayed at the same place the hole time even when i slowed down to about 40 they stayed the same. once i put it back into drive the rpms went back down to normal. weird huh. is this supposed to happen or what??? any info would be great. thanks

The engine speed is controlled by the computer, using inputs from the TPS, Crank sensor and a few other parameters.
What you experianced was a normal operating condition.

ok, so you're saying that the sensor for the rpms is not connected to the motor at all, weird, oh well. thanks for the answer though.

NO, what jdmcivic04 is saying is that the ENGINE SPEED (rpm) is controlled by the computer , etc. and that the engine speed is accurate as reported by the tach.