Q: Car jerks at a stop, only when AC is turned on.

asked by on November 13, 2017

I've been having this issue for months now. Whenever I come to a stop, whether it be a stop sign or red light, my car jerks and kicks, this ONLY happens when the AC is turned on, I've driven the car with the AC off numerous times and it never has that issue. So far I have replaced the mass air flow sensor, the idle air control valve, PCV valve, the throttle position sensor, and I have also cleaned the throttle body as best I could, none of this has solved my problem.

My car has 118000 miles.
My car has an automatic transmission.

Car idle is rough Inspection $94.99 - $114.99 Get a Quote

As you may know, the AC system puts an additional strain on the motor. The air conditioning compressor requires torque from the belt system on the engine to power it. When the AC is off, the compressor clutch does not activate, meaning the AC is not straining the engine. When the AC is on, the compressor clutch activates, wherein the drive belt on the engine now turns the compressor which in turn is compressing refrigerant so you can be nice and cold. The Idle Control Actuator is what controls the engine idle. When the AC kicks in, the engine will drop some RPM, and the actuator opens to allow more air into the engine. When you are at speed, the throttle is open from the accelerator pedal under your foot. the Idle control actuator is not active at this time. I would suggest having an exert from YourMechanic come to your location to take a look at the vehicle to verify what may be causing the rough idle.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

How do I cancel cruise control?
There are three easy ways to cancel the cruise control: 1. Press the CRUISE button, which is located on the steering wheel. 2. Press the CANCEL button, which is located on the steering wheel. 3. Press the brake pedal. When...
AC is not working
Your air conditioning not working is most likely due to the refrigerant in the system being low. Over time the refrigerant will slowly leak out. You won't be able to notice it because it is a gas. You will only...
Speakers not working
It sounds like the amplifier is not working. Check the fuse for the radio amplifier. If its blown, replace it with the same rated fuse and see if the sound comes back. If not, the amp has most likely failed....
Auxiliary battery draining the hybrid battery
Auxiliary batteries can take awhile before symptoms may be noticed on a Prius. This is due to the hybrid system powering many of the components. In this vehicle the auxiliary battery is mainly used for starting. It could cause problems...
car sat for 14 days and now won't start even after turning it off after jumping it.
From what you've described, it sounds like your battery is not capable to hold a charge anymore for long periods of time. I suggest having the battery and charging system checked. Have a certified technician, like one from YourMechanic, diagnose...
what does it mean when your car starts knocking in the front near the tires?
Hi there. The best way to diagnose any problems with the front end is to have a professional mechanic take a test drive. However, the symptoms you are describing are similar in many ways to worn out brake pads (https://www.yourmechanic.com/article/symptoms-of-bad-or-failing-brake-pads)....
Clutch will not engage and has no pressure. What is the worst case scenario and estimated cost for repairs at a dealer?
Hi there. From the description you have provided, your clutch will not engage, has no pressure, cannot engage any forward or reverse gears, is difficult to estimate the cost of repair at a dealer. Diagnosing the inoperative clutch, would help...
Why is my 1997 Nissan Maxima bogging down and stalling.
Hi there. Though there are a lot of reasons that will cause this most of the time on this vehicle it is due to a failing crank or cam sensor. both are common failures. I usually start by scanning the...
2005 kia sedona has no spark, no bad fuses, replaced computer, battery voltage at each coil, fuses all appear to have battery volt
You may have a defective crankshaft sensor? If you check computer with a scanner for codes and a rpm signal from crank sensor and if none then replace sensor.

Related articles

A Buyer’s Guide to the 2012 Ford Escape
CUVs CUVs (Crossover utility vehicles) are becoming more and more popular these days, as consumers are interested in saving money and buying more eco-friendly vehicles but they still have a lot of people and cargo to move around. CUVs like...
The Best Used Cars to Buy If You're Over 50
Shopping Shopping for a car when you’re over the age of 50 begins to shift a bit, as your priorities tend to change. Suddenly it’s not so much about what the vehicle looks like, or how much space it has...
The Best Used Cars to Buy to Maximize Resale Value
A A car is not an investment. An investment, by definition, increases in value. A car is a necessary purchase, and it will never appreciate in value, with the possible exception of classics and antiques. So, as a used car...