I searched around and didnt see anything about this exactly, but I start the car it goes up to 3000 then 1500 then 1100 then 750 but it will bounce back and forth from 750-300 it sounds like it will ALMOST die but it catches itself. This is sitting still tho. I was driving it and I would push the clutch in and it did die on me. think its my TPS maybe? Its my first RX7 a 1990 GXL 70,000 miles altho it has a new used engine in it that may or amy not ahve mroe miles than that, but the compression is good on it and it runs smooth just doesnt idle (plz dont flame I know iam a noobie)

 

Vacuum leak or TPS is good place to start...lots of TPS info if ya search in here

 

Yup. The starting at 3000, 1500, 1100, 750 is perfectly normal.

I'd go ahead & change the plugs and wires, if they haven't been changed recently (or just pull the plugs & clean them if the have) as well. A weak spark could cause that.

What happens when you jumper the initial set connector (green, in the front driver's side corner of the engine bay)? That should pull the computer's adjustments entirely out of the loop. If it's still bouncing (or if it just quits), you may have a clogged injector or such.

-=Russ=-

 

In addition, check the miserable BAC valve for internal leakage past the seal.