Car stalls if i turn on A/C
 

It is summer time and it is hot as hell so i would love to feel the nice cold air from my a/c but every time i turn it on my rx8 stalls. If i put it on level 1 the car just idles really rough but if i go over to levels 2-4 it stalls. I have searched everywhere for the last 3 months and no solution. Can anyone help me solve this.
Do i need a stronger battery such as an optima or what is going on?
Current battery has 750 Cranking Amps 600cca Duralast
Also the air pump is giving a screeching noise but i don't think that has anything to do with the stalling.
2004 Mazda RX8
4 speed automatic
original miles-85xxx
on motor-37xxx
Installed new ignition coils
new MAF sensor
Supposedly new spark plugs from previous owner (they do look new and in good condition)
Also people have said to check for the engine mounts but that has nothing to do with the dropping of rpms

Do your light go dim? When your at a stop and rev the engine do they get brighter?

Could have a bad Alternator or battery.

Clean your connection first.

Otherwise could be a bad cat, but most likely the Alt/Batt

No the lights don't do anything like this but I will try and check the connections. How would I check the cat? Is there some sort of device or...

I'm sorry if this is a dumb question but I have the same exact issue, same conditions too as far as plugs, coils, and MAF; though my cat is gutted. Why would a bad cat cause this issue?

Wouldn't be the cat. Are there any codes stored aside the ones for the missing cat?

Inability to idle with the increased load is either poor MAF measurement , vacuum leak or poor battery connections. If the intake is not original that might be a clue.

did you try to rotate the magnetic clutch cover on the front side of the pulley to make sure the compressor is rotating easily? It seems more likely to me that the compressor may be seizing up internally.

because the compressor only uses a hp or two when operating properly.

if you feel like it’s more a weak/worn engine then measuring the intake vacuum level at idle is the first place to start. It would have to be fairly low for a properly functioning AC compressor to drag down and kill the engine.
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