Skip the auto shop - Our mechanics make house calls

Q: I have a stutter at idle

asked by on

My Stratus has developed a stutter at idle. Specifically, when the ac is on. This problem started about 3 months ago and appears to be getting worse.

When the car idles without ac, it sounds good and sits between 900 and 1000 rpm. When the ac compressor kicks on, it drops to 750 rpm and stutters, shaking the car and engine and dropping the idle as low as a couple hundred. It will kill the engine completely if I dont give it gas.

The car runs great and doesnt appear to have any loss of power at speed, even if I'm at a very low speed with the ac on it does great.

Now here's the kicker: it had these symptoms for a couple months and I was told it was the ac compressor. I replaced the ac compressor properly and now have ice cold air, but the problem remains.

I have also replaced the idle air control valve, air filter, spark plugs, oil, and had the battery and alternator tested (both came back perfect).

I'm at a loss for what else it could be. Help!

My car has 169000 miles.
My car has an automatic transmission.

A: I would recommend checking the mass air flo...

I would recommend checking the mass air flow sensor. As you know this also contributes to the regulation of air flow into the throttle body. If this does not have the proper voltage going to it, this may also cause a drop in rpms since the ECU detects the change in voltage as a change in air flow and will adjust fuel accordingly. I would recommend having an expert from YourMechanic come to your home to diagnose and possibly replace your mass air flow sensors.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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

Get a quote

What others are asking

Q: Belt tensioner broke 2006 Cadillac DTS

Hello - yes, the serpentine belt (aka accessory drive belt) drives your water pump as well as the alternator, power steering pump, etc. Failure of the belt or tensioner means hot water in the engine is not pumped to the...

Q: Drove through high water

Hi there. From the description you have given, driving through the high water, your vehicle stall, and no crank situation may be the engine hydrostatically locked. The engine took water in through the intake, into the cylinders, preventing it from...

Q: I cannot find the neutral safety switch. Where is it?

The neutral safety switch on this transmission is called a transmission range sensor. The sensor is located on the right front of the transmission looking from the front of the vehicle. The connector should have an 8 pin connector on...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...