I just picked up a 88 rx7 convertible non-turbo. When you sit at idle the rpms are really low and it sometimes dies. Any suggestions on a fix?

 

The air bypass screw can be opening to raise overall idle. And the variable resistor can be adjusted to smooth out your idle. Adjustment requires jumpering the initial set coupler; a manual will show you where that is, or you can see if you can find it with the search function.

 

If your idle fluctuates at all, you may want to also check for a vac leak. They will cause your car to stall as well.