Bad engine misfire while AC is on?

Also, when i hold the window switch down (while parked) the rpm drops and starts it to hesitate.

The misfire while AC is on is so bad that the engine continues to shake the car for a few seconds after the engine is turned off.

2000 ford focus, 2.0L zetec engine

Added (1). replaced within last year;
-alternator
-spark plugs
-fuel injectors
-fuel filter
-transmission filter
-air filter

while changing the fuel injectors i noticed some water or oil pooled inside the intake manifold below throttle body, misfired before they were replaced but got much worse after a heavy rain storm while driving through a muddy road.

The possibilities are endless. If everything is fine with it off, pay a mechanic.

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