ok so it probally was the Air control valve he changed then, my error, will have to check the voltage meter in a few mins. I'll let you know....

voltage goes immediately from 14 to 13 and the car dies or drops down to stall as soon as the AC is turned on and the car is stopped

'If' the voltage drops moments before the stall then perhaps that is the problem. If the car continues to run at 14 volts regardless of whether the A/C is on or not but does not run at 13 volts then that itself could be an issue.

the voltage reading fluctuates, no trouble starting, 13 - 13 1/2", then 14" once your going on the highway, it is a New battery, the voltage didn't drop until or as the car idle was dropping.
When you first start the car while the engine is cold it revs at 1200 rpm for the first couple of minutes. During that time, if you turn on the AC, the engine revs higher like it is suppose to. Once it is warmed up, with the AC off, the revs drop down to 1000 and if you try turning the AC on then or thereafter, the revs will drop down low enough to stall everytime. I can be driving 50 mph after the warm up period and once I push down on the clutch without giving it gas it will also still stall only if the AC is on.

W/the engine idling cold right after starting the car the voltage output of the alternator should be 14.4 volts. Normally, as the engine heats up the heat can affect the output of the alternator but it should not drop below 14 volts. Measuring the output of the alternator should be done using a voltmeter connected to the output cable of the alternator (volt meter gauge is not the most accurate nor is it precise to read). Thus the charging system might be contributing to your problem.

ok I have to buy a voltmeter, to check it this out, thank you so much and I'll reply when I can do this, have a nice evening

question, if the air control valve is associated with the air pump (which has no belt) so it's not in operation, would this affect the idling issue?

I'm thinking about tackling the BAC unit, afraid to remove it, but I guess it wouldn't hurt to try and get it cleaned.

guess not, I can't even remove the large air hose to get to it, Oh well I tried

The ACV is emissions related thus it should not affect the operation of your car unless it was leaking vacuum.

alright thank you, was wondering of this

I haven't done anything as of yet for the stalling issue, but my son drives the car to work and yesterday he said (on his lunch break) that it actually stayed started with the ac on, which is unusual, he said he did put the window down and it did the stalling thing and again when he put the window back up, so you may be (Satch) absolutely correct on the battery power issue. So I need to address this eventually. The clutch pedal is now sticking, so this is probally more important to address before it goes out completely. I checked the fluid and filled it just alittle, it seems to be using this a lot, if this helps at all. Like every few days it drops like an inch, inch and a half

I just read on "fix ya" site that it could be the hose (dry rotted) leading to the slave cylinder or the actual slave cylinder itself, I'll check the hose when the car gets here, that slave cylinder does look pretty rough! Is this the correct part I need if it's out? http://www.ebay.com/itm/New-Clutch-Slave-Cylinder-Mazda-RX-7-91-90-89-88-87-86-1991-1990-1989-1988-1987-/230803596169?pt=Motors_Car_Truck_Parts_Accessories&fits=Year%3A1990%7CMake%3AMazda%7CModel%3ARX-7&hash=item35bcf76389&vxp=mtr

I just went ahead and ordered it since it's not very expensive and sure looks like it needs to be replaced, I'll have it anyway if it is or becomes an issue

took a flashlight and I do see brake fluid? on that rubber acordian looking piece attached to the slave cylinder, so here's hoping it's the slave and not the master, too

read from the FSM troubleshooting that a sticking clutch means lubrication is needed in different areas of clutch system, will I have to take it to a mechanic for this?

there isn't much to "lubricate".
The Throw out bearing is factory lubed (when I put another in I just grease the shaft a touch.)
The rest of the system is pretty well hydraulic.
The Slave pin rests on a fork at the top of the trans and if you wanna dab some goop to that knock yourself out..

Really If you replace the master,hose and slave(and If the clutch was working correctly before the hydraulics went out on ya) then you should be good to go.

TIP: just remember it is not a "special Car"..it's just a Older car that needs maintenance.So if anything you can fix on a "piston car"..you can DO on this one.
They are not unique..they just have an engine with different internals.
After that the Shit is the same!

I'll replace the slave cylinder when it arrives and bleed it of course. Hopefully that will do. Thank you very much for the information, as I was just going by the FSM online as far as the lubrication

Decided to go ahead and do another test, the mechanic said he got them all to clear a month ago or so, well it's sending something, here's the video to follow this post of the test. Any input appreciated as always.

is that an 18 code? or was a 10 and an 8 ?

Code - Input Device - Fail-safe operation mode
o 01 - Ignition Coil (Trailing) - Trailing ignition pulse cut
o 02 - Crank Angle Sensor (Ne) - Fuel Injection and ignition cut
o 03 - Crank Angle Sensor (G) - Fuel Injection and ignition cut
o 08 - Airflow Meter (AFM) - Basic Fuel Injection and fixed timing (Cripple mode)
o 09 - Water Thermosensor - Coolant temp fixed at 176F
o 10 - Intake Air Thermosensor (AFM) - Intake air fixed at 68F
o 11 - Intake Air Thermosensor (Engine) - Intake air fixed at 68F
o 12 - Throttle Sensor (TPS) Full Range - Fixed at 20% open
o 13 - Pressure Sensor (intake manifold pressure) - Fixed at 29.9 inHg
o 14 - Atmospheric Pressure Sensor (Inside of ECU) - Fixed at 29.9 inHg
o 15 - Oxygen Sensor - Feedback cancelled
o 17 - Feedback System (poss O2 sensor) - Feedback cancelled
o 18 - Throttle Sensor (TPS) Narrow Range - Fixed at full-open
o 20 - Metering Oil Pump (MOP) position sensor - Basic Fuel Inj and fixed timing
o 27 - MOP (General) - Basic Fuel Injection and fixed timing
o 37 - MOP (General) - Basic Fuel Injection and fixed timing
Code - Output Device
o 25 - Solenoid, Pressure Regulator Control
o 26 - MOP (Step Motor)
o 30 - Solenoid, Split Air Valve
o 31 - Solenoid, Relief Valve
o 32 - Solenoid, Switch Valve
o 33 - Solenoid, Port Air Valve
o 34 - Solenoid, Bypass Air Control (BAC) Valve
o 38 - Solenoid, Accelerated Warm-up System (AWS)
o 40 - Solenoid, Auxiliary Port (6PI) Valve
o 41 - Solenoid, Variable Dynamic Effect Intake (VDI)
o 51 - Fuel pump resistor relay
o 71 - Injector (Front secondary)
o 73 - Injector (Rear secondary)

I'm not sure, that's why I placed video, I think maybe a 10 then a 8??

if the BAC is possibly my stalling issue, would I not get a code 34 or even the 38 for AWS?

No.

ok, just replaced the slave cylinder, going test drive it and the ignition will not turn with the key??