Civic EG

My car civc eg8 but engine is single carbd..like d13b2...
My problem is car is idle smooth without load..
But when I turn on headlights car getting vibrate (AC OFF)..
also rolling up shutters, turning steering wheel , press brake car gets vibrate...
But with AC ON.. no vibrates. ..and I feel when I put ac engine gets rev up as usual...
what will occur???
Plz help....

Fyi- ichked all my drive belt s are in good condition. .
chked battery without load-13 and withload (ac on, headlight on)-14.5 amp

When the car shakes, it is because the engine is about to stall? Does your car have a tachometer? If so, what rpm is your idle and what rpm does it dip to when you have a load?

i dont have tachometer....