Please start reading the FSM link I gave you and do some research.

http://www.wankel.net/~krwright/cars/rx7/85_manual.html <----Direct Link to your 1985 RX-7.


4B - Fuel & Emissions
http://www.wankel.net/~krwright/file...ssions_13B.pdf
Page 64 of this link will tell you the idle speed and mixture and setting them.

 

thank you again this way helpful and goodnight

 

Wankel go put-put
Wankel put-put bad
We make Wankel put-put good!

 

yea every time is come to a stop it has the fluctuation 95% of the time the other 5% it idles normally when i come to a stop

 

The fuel delivery system needs to have a vent in order to deliver a consistent fuel pressure, just like the carburetor needs to be vented to work properly. But it's not safe to have fuel vapors lingering about, and they also contaminate the atmosphere. There is a solenoid that controls the vent to the carb, and when the car is on it opens, and fuel vapors that would be exposed to the atmosphere are simply sucked in and "metabolized" by the engine and emissions system.
But the fuel delivery system needs to have a bit more extravagant vapor recovery system to keep from exposing fuel to the atmosphere. That's what the charcoal canister is all about.
If the vent system is blocked or a hose is kinked, etc, then you'll have idle problems because the idle is basically gravity fed, so it's very subject to tiny changes in atmospheric pressure.
A tell tale sign that this is your problem is if your tank "whooshes" when you remove the gas cap.

 

I agree with Sterling, check the vacuum hoses. I had a melted one that caused a idle flux and a bogging on acceleration. The hose that melted on me apparently is a common hose to melt. Its located by the fire wall running from the back side of your carb down into the engine, its called the anti-afterburn hose. You may wanna check that out.

 

His car is FI, he said so in his first post.