dumb question about my car

[Mustangless]

When it is just idling and I turn the wheel just a little the rpms will go down for a few seconds then back up. Is it supposed to do this, or is it normal?

 

[rgs]

same

 

[S/CBlack95GT]

Tis be normal. If your idle is a little low the computer will sense the load caused by the power steering pump and it will open the IAC.

The same thing happens when the A/C compressor kicks in.

 

[V8302stangs]

What about when u are coasting in neutral how the rpm sits at around, say, 1000 rpm but once the vehicle gets below 5mph it drops down to aroun d 800?

 

[S/CBlack95GT]

What about when u are coasting in neutral how the rpm sits at around, say, 1000 rpm but once the vehicle gets below 5mph it drops down to aroun d 800?

That is set by the computer reading the VSS (Vehicle Speed Sensor) which is in the transmission. It is totally normal as well.

 

[V8302stangs]

That is set by the computer reading the VSS (Vehicle Speed Sensor) which is in the transmission. It is totally normal as well.

Any idea why they have it do that?

 

[HISSIN50]

Any idea why they have it do that?

For safety concerns. Picture having been on the freeway cruisin for some time at night. You hit the off-ramp and toss it into neutral while negotiating a sweeping turn as you slow down. Then the motor seems like it wants to stall (load from PS, brake lights, perhaps your fan kicked back on now that it is below the speed threshold, etc). Not good.
The elevated 'rolling idle' is a good thing just for this.

 

[V8302stangs]

ah makes sense