popping sound when i put on A/c, losing power too!

I have a 95 beretta, 5 speed 2.2 .
I have noticed lately, a loss of power, and sometimes the car just stalls, when the fan goes on, mainly with the a/c.
The engine sounds find idiling, but does sputter a little when given gas.
The strange part is when the a/c is turned on, an immediate noise begins.
The best way to describe the noise, is a popping sound, like when someone is popping popcorn. When i turn the a/c off, it immediately stops, and the idle seems strong.
The location seems to becoming from around the left side of the engine, near the battery, but below it. I see no sparks, but the popping is constant with the a/c running, and stops immediately when the a/c is turned off.
And like i said, the extra load when the a/c is turned on, is also making the car not idle correctly.
Anyone familiar with this POPPING sound, or what procedures i should use to diagnose the problems
Have the Haynes, so please tell me what chapter to turn to.

Look at the A/C clutch when the A/C is turned on....is the noise coming from the clutch or compressor? May have a bad compressor that is putting a load on your vehicle......remove the belt, and grab the clutch(not the pulley), and see if you can easily rotate it.....

Remember this can happen when you turn the the mode switch to defrost, because the A/C will engage in this mode...

Does the engine run rough/stall, ONLY when the A/C clutch is engaged? Or do you also feel this when going up hills under a load?

Look at the A/C clutch when the A/C is turned on....is the noise coming from the clutch or compressor? May have a bad compressor that is putting a load on your vehicle......remove the belt, and grab the clutch(not the pulley), and see if you can easily rotate it.....

Remember this can happen when you turn the the mode switch to defrost, because the A/C will engage in this mode...

Does the engine run rough/stall, ONLY when the A/C clutch is engaged? Or do you also feel this when going up hills under a load?

When the car starts, it doesn't run bad, but something is not right, when i give it gas, there is a little bit of a sputter.
When the fan comes on, its not bad, but when the a/c along with the fan comes on, and the car is idiling , that popping starts, and it will start to lose power, and eventually will stall out.

The noise is coming from that area around the 1 part that is gold in color, looks kind of like a flying saucer, and i can't think of what the name of that part is, but the pop is in that area.
Compressor is on the other side, and the a/c as usual, is ice cold.

You may have a valve that is not opening fully due to wear. It would be caused by a worn camshaft lobe or it could be a problem with the lifter/push rod/rocker arm assembly. I eventually had a poping noise anytime I pressed the accelerator on my '90 Celebrity, 3.1L V6, and it was caused by a worn camshaft lobe. I had not been changing my oil regularly because I was adding a lot (mistake), and the sluged robbed one of the camshaft lobes of lubrication. The exhaust valve for that cylinder stopped opening, but the intake valve was OK. The "pop" noise came from when the intake valve opened. It was somewhat random because the mixture in that cylinder was not always right since exhaust gas was pushing back on the intake gases.

The best way to check is to pull the valve cover, remove the plugs and rotate the engine with a ratchet or bar. Check for proper valve lift on each of the valves. They normally move ~ 1/8" - 1/4" (exact specs are available if you have an indicator gauge).