1992 Toyota Celica Engin cuts out while driving unless A/C

Electrical problem
1992 Toyota Celica Front Wheel Drive Automatic
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Engin idles ok, increase engin rpms with A/C fan switch off engin pulses - like loss of power or fuel.
Turn A/C fan switch on and engin smooth out and runs normal.

No one has been able to locate the problem.
HELP!