I own a 94 Protege. When my car is at a red light for a long time and the AC is on, the car dies sometimes. It starts right back up though.

Possibly when the AC compressor kicks in it puts a load on the engine and the engine does not maintain idle RPM.

I'm not positive what part is causing the issue. Suggestions have been the Idle Air Control Valve, Idle Air Control Motor, the Throttle Position Sensor. Does anyone know what parts could be causing this problem?

It may be the part with the plunger device inside it that is not pushing down properly? We did a test and turned on my car in the driveway with the AC on, and this part appeared not to move. What is this part called?

Any assistance on this is appreciated!

 

They call it a bypass air control valve. Same thing as an idle air control valve. At idle with the A/C on tap it lightly ( i use a brass hammer) and if the idle comes up it was just stuck. You can clean it and the throttlebody and sometimes have success but it has an electric motor in it that sometimes gives up which is a bit tricky to repair.

 

When I saw this post, I thought the same thing and was going to say that too. But isn't it a solenoid that simply opens w/power to it and closes w/o power??

 

It is an electric motor working a plunger constantly adjusting. If you don't clean the throttlebody regularly carbon builds up and causes the plunger to stick and the motor to overheat.

 

You don't say mileage, history of prior symptoms/ repairs, any intermittent CEL, fault codes etc. so I'm having to guess.

In order of easiness:
1. Splits in corrugated air intake duct (hard as hell to see, you have to unclip the air filter and flex the ducting to detect them). Easy and cheap to fix.
2. Idle air control (IAC) valve sticking. Remove clean, test, replace if needed.
3. Exhaust Gas Recirculation (EGR) valve sticking and/ or ports clogged with sludge/ carbon deposits and/ or spindle fouled by varnish and/ or rust. Remove, clean (VALVE AND PORTS), test, replace if needed, making sure you have a good seal with the intake manifold. Mazdas have a history of EGR problems which needed two redesigns
to fix. Canadian models finally had to have a complete rehash with a heater jacket incorporated in them to prevent exhaust condensate from corroding the valve stem, and Mazda put an unlimited mileage 7 year warranty on EGRs.
The EGR is a pig to remove: you have to use a thin wall 10mm. socket with swivel end.
Once out, the 4 philips head screws are easily damaged too, so use lots of releasol, hair dryer, tap gently on the heads with a piece of hard steel rod to shock and awe them first, then be very careful and patient. If you can, get rid of those screws and replace them with stainless steel square slot types.

If the EGR ports are carboned up, getting rid of that mess is no picnic either, and if you don't do it right, residual loosened sludge will get into the EGR proper and in no time you'll be back at square one.
Putting the EGR back, be sure the gasket is OK, surface clean, and the mtg. bolts are torqued properly; idle problems due to EGR/ manifold leaks are a common problem too.

P.S. I think Virgin 1 is right, and it's a solenoid type operated by manifold vacuum switch; I don't think Proteges ever used the vibrator/ stepper motor type of EGR. My '99 1.8L FP engine is definitely a solenoid driven type.
You can google the web for good in depth info on the EGR issue.