Q: Car runs rough with AC on

asked by on June 29, 2017

My car drive perfect without the ac on.as soon as I turn on my ac I feel a vibration on my steering wheel

My car has 119000 miles.
My car has an automatic transmission.

It sounds like you may have a bad AC compressor or potentially a faulty MAP Sensor. When the AC compressor is beginning to fail, this may incur an increased load on the motor as it works harder than usual to turn a bad compressor. This increased load causes the motor to work harder than it otherwise normally would, resulting in the motor overheating.

The Manifold Absolute Pressure (MAP) sensor senses engine load and generates a signal that is proportional to the amount of vacuum in the intake manifold. The engine computer then uses this information to adjust ignition timing and fuel enrichment. When the engine is working hard, intake vacuum drops as the throttle opens wide. The engine takes in more air, which requires more fuel to keep the air/fuel ratio in balance. When the computer reads a heavy load signal from the MAP sensor, it adjusts the fuel mixture to slightly more rich than normal so the engine can produce more power. The computer will then retard (back off) ignition timing slightly to prevent detonation that can damage the engine and decrease performance. This may also be caused by other closely related components such as a dirty or failing mass air-flow sensor, a faulty throttle position sensor or potentially a vacuum leak. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.

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

What others are asking

Nissan Frontier VS. Toyota Tacoma trucks

Tacoma by far. The Nissans are decent, but unfortunately, Nissans have been going down the hill in the last decades and Toyota is still standing pretty good. You are not going to get life out of Nissan that you...

Poor starting when cold

https://www.yourmechanic.com/article/how-to-start-a-car-in-cold-weather This is an article that talks about starting a car while it is cold. It is very informative and I believe it is relevant to your situation. You also may have an issue with your fuel. If it was...

Intermittent ticking sound from front of engine

If the ticking sound seems to be dependent on temperature, I might suggest taking a look for an exhaust leak somewhere. Small exhaust leaks will normally begin when cold and diminish as the engine warms, but in my experience, I...

Ordered 37×13.50R20 tires and 20X12 rim I have a 4 inch lift kit by ready lift. Want to upgrade gearing from 3.73 to maybe 4.88?

Hi There, I have heard good reviews about a couple of the following shops in your area: http://www.tricktrucks.com/ http://www.bowiepowertrain.com/Bowie-domestic-auto-repair.html http://nolimitbmore.com/services/

Start problem with good crank.blown head gasket.

Hi there: In most cases, the symptoms of white smoke and needing to add coolant frequently mean you have a blown head gasket. It can cause inconsistent starting problems as you've described, but it's also possible that the crankshaft position...

Could you help me out with the price of shock absorbers please? Cruze 2008.

Sent billing question to CS about pricing shock absorbers and having them installed.

Reduced engine power, tire pressure symbol, and AC noises

Hello. From what you describe it would appear that your vehicle may be experiencing more than one issue. The exclamation mark and tire symbol come on when the vehicle's tire pressure monitoring system is set off. This occurs when the...

How do I reset anti theft on a Hyundai Santa Fe?

The vehicles systems can be reset just by disconnecting the battery for an hour and all fault codes are usually cleared once the power is disconnected. however, this will not clear any problems with the vehicle. If there is a...

Fuel EVAP line that runs under car is kinked how do I know if it is leaking? Also can I drive it like that if it's not leaking?

Hi there. In most cases, an EVAP leak will create an OBD-II trouble code, which is the best way to detect an EVAP leak. By having a professional mobile mechanic complete a check engine light inspection, they will be able...

Related articles

2012 Nissan Sentra vs. 2012 Nissan Altima: Which One Should I Buy?
When you consider the Nissan Sentra versus the Nissan Altima, you need to realize that you’re crossing between two different classes of vehicle: the Altima is a mid-size sedan while the Sentra is a compact sedan. The differences between the...
2007 Nissan Versa vs. 2007 Saturn Ion: Which One Should I Buy?
Compact cars as a class are generally meant to be commuter vehicles: with excellent gas mileage, an entry-level price point, and decent safety ratings for those who are on the road the majority of their time. These cars also make...
The Top 5 Selling Cars in Alabama in 2012
2012 2012 was a great year in Alabama for auto manufacturing, but that wasn’t the only bright spot. Vehicle sales in Alabama were also robust in 2012. Nothing much changed in terms of the vehicle types that were most popular...