2003 Ford Focus Wagon jerking slightly when A/C is on

ford
focus
airconditioning

#1

My car jerks slightly when I turn on the a/c but it still runs cold. Worked perfectly fine last year.


#2

What engine? How many miles? Check engine light on? Define 'jerking slightly." Jerking while driving? During shifting? does it not “jerk” when the a/c is off? Any other symptoms? Any work done recently?


#3

My 2002 Miata jerks when I turn on the AC. With a small engine and a light car, the sudden addition of the load from the AC compressor will make the engine react with a sense of loss of power, which is exactly what’s happening. The AC is sucking up some power. Once everything is running there’s no more jerking, but the car definitely has less power to accelerate.


#4

Sometimes noticeable on my 1999 Honda. I think looseness or tightness of the v-belt that drives the compressor is a factor. On cars where a serpentine belt drives the compressor, a glazed belt or worn sprung pulley could also affect it.