THIS PROBLEM CAN BE SOLVE WITH ONLY ADJUSTING 1 SCREW! (in the event that all components are working properly). The best way to know that u only need to adjust the screw is.

1) Engine only gegar when you open the aircond
2) But when you press the accelerator, it become normal.
3) This only happen when you are in IDLE mode. When you are driving (press the accelerator), everything is good "even with aircond".
Yaa..seriously..only 1 screw (actually 2, there are 1 more at the back if u want to make it balance) i also have the same problem. Terbang RM 70 (Tuning + change spark plug) for nothing when hand it  to mechanic. The mechanic dont tune it properly so that i need to go back there to change another part that he suggest " some aircond actuator-thingy". Lucky me i am a fast learner, i see the whole process when he tune the engine. It's just a matter of pusing a screw to adjust the rpm when in idle mode. I AM NO EXPERT IN CARS AND DONT KNOW ANYTHING ABOUT THE COMPONENTS IN THE CAR. BUT I MANAGE TU TUNE IT at around 1.1 rmp when ideling!!. THE PROBLEM "SHAKING WHEN AIRCOND IS ON" vanish!!. If  only i had this knowledge yesterday. I save RM 70. The spark-plug in my opinion is not necessary. Most kedai want to tapau ur money only. Do a little experiments on ur car.    . Will attach the picture of the position of the screw later.

To remove suspense, you may refer to the picture of post #2399 in the link below.
https://forum.lowyat.net/topic/2900268/+2380

If the air con idling adjustment does not change even after adjust, then it could be the gold coloured round thing tht screw attached to it (called air con idling vacuum pump or 'vacuum actuator' in the pic) is spoilt. Pls make sure it is Denso brand when replacing. Cost about RM 90 few years ago. Local brand costs half the price but only last few months. Denso last for years. I purchased the Denso part from a spare part shop in OUG years ago.

Pls also check for vacuum hose for leak (those small hoses) as they tend to crack at either end of joint. It will cause the adjustment take no effect.

Note:
1)You need to rev a bit after each adjustment for new setting to take effect.

2) Proper way is to adjust the base timing without the air con screw then only adjust air con idling screw.

without air con should be ard 800 to 850rpm and with air con ard 950 to 1k rpm.I dont have the factory spec for exact figure.

Looks like your fast idling is not working. To get the it to work 3 items must be working
1) air con vacuum pump /vacuum actuator.
2) FICD (carb version)
3) vacuum hose not leaking and correctly attached.
For hose it should be run from engine block to ficd (denso carb version) and another hose from ficd to a/c vacuum pump.

Yes, the proton wira carb has ficd as well. LMST shld hv as well as using the same drivetrain. It looks like toyota ficd, attached to firewall with 2 small vacuum hose attached to it.

Last time,not working, I changed 3 items after fed up workshop doing it using generic local parts. Item 2 seldom spoilt but I changed it as not tht expensive.

1) approx m90 (oem denso for carb)
2) approx rm 80 (oem denso)
3) vacuum hose rm 2 for 1 feet ( abt 4 to 5 feet )
(price quoted is few years ago)

Correct vacuum connection is priceless..as even changed all 3 items but connection is wrong, fast idling (i.e with air con on) will not work.

Yes..If set properly and fast idling working, the rpm will drop a bit when air con on and then climb bk to slightly higher.

The fast idling is mechanically activated, tht explain the delay is more than electronically controlled.

If u need to set the rpm of air con off higher to compensate the load imposed when air con is switched on, tht explain tht fast idling mechanism is not working.

From my experince, the correction of fast idling load should be 2 to 3 sec. The 1st thing is to ensure related hoses fit tight. Over time the hoses expand at the join end (bulging effect) causing it not air tight. Can cut at bulging area if the hose still have enough lenght. Not suggesting you to do that but thats maybe the root cause.Best to take out the hose to inspect. It could have micro crack.

Since it did climb back, but take longer, it shows the fast idling mechanism work but may not be optimum. I didnt adjust and dont think there is any adjument screw on the denso ficd for carb version. Maybe Proton changed the FICD supplier for newer batches.

Your hose connection looks correct based on your photos. Raw suction from engine block to FICD. Ficd block suction to a/c vacuum pump when air con off. When air con on, the ficd open the valve for suction to a/c vacuum pump, in turn pull the carb cable to add more air/fuel mixture.

For your reference on the adjustment screw at Toyota FICD for fuel injected car. Looks to me redundant for carb as there is adjustment screw at a/c vacuum pump (efi dont have  a/c vacuum pump and rely on ficd screw for adjustment).
http://www.diytacra.com/2010/11/ficd-fast-...device.html?m=1