Ac compressor.

[pussiwillow]

Since I've had my car, the Ac compressor kicks on and off regularly, sometime while shifting causing it to jerk bad, low speed in low gear makes it jerky, the highway not so bad but annoying. Is it normal operation for it to kick on and off? No leaks, pressure is dead on.

[gpelite]

Yes it is normal to kick on and off, but it should never dip your system to that extent. It should click over and you should get slightly less pedal power because now the clutch on the unit is drawing power to that pulley. Your power consumption is beyond your battery and alternator output so one of them or both is failing. Might not be "OMG READY TO DIE" but aged.

I usually point at battery for a switch on draw of power, their usage once the car is started is to retain power and provide spikes with necessary stored power. With that being said everything with the battery comes into play so clean and tighten up your terminals, a bad connection to the power your car needs is as bad as a failing battery or alternator.

There are 1000 DIY alternator tests as well, without removing it from the car. Invest in a cheap walmart multimeter or ebay one. Follow the testing (basically you test for voltage to the battery from the alternator by simply touching leads. 12.2v or 12.3v or less is barely alive while engine on, 13v is peak and mint.

Also if you are running aftermarket stereos or equip, get a capacitor for it or your main line. The problem will vanish.