Q: Rough idle an shakes when stopped

asked by on February 27, 2017

When I'm driving the car does great but when I come to a complete stop the car wants to shake an try to die it doesn't do this in neutral or park..

My car has 187000 miles.
My car has an automatic transmission.

This may be a sign of a faulty MAP sensor as the vehicle responds adversely to a load put on the motor (i.e. putting it in gear, turning on AC or engaging the brakes). 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]((https://www.yourmechanic.com/services/manifold-absolute-pressure-sensor-map-sensor-replacement), 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

Idling low at 1 to 1.5k rpm. can not get rpms above 3k.

It sounds like you may have a couple of different issues going on here. At idle your car should be hovering around 750-800 RPM's consistently. This is generally controlled by the idle air control valve which a valve that reads...

Power steering not working.

It sounds like your serpentine belt is broken. You can inspect the belt under the hood in front one the motor. If the belt is OK you may have a bad power steering pump. I recommend having a technician come...

car won't turn over, clicking noises

Hey there. Sorry to hear about your issue with your 87 Acura Legend. That loud clicking noise on the right side of the motor is typically an indication of a broken or lose fitting wire on the starter. A common...

Transmission not working properly

Hi. P0133 is a code for the oxygen sensor bank one sensor. P0410 is a code for the secondary air injection system malfunction and a P0301 is a code for a misfire on cylinder 1. I would suggest having a...

Small fire under hood

Even small fires can cause a lot of damage, but the engine bay is designed to deal with high temperatures. Have an experienced mechanic, such as one from YourMechanic, come out for an inspection of all of the underhood components....

Car shuts off when the weather is hot

Hello. A bad cam position sensor will cause a Check Engine Light to come on and possibly cause a stall or no start condition for your 2000 Mercury Mystique. Cam position sensors usually develop their problems when hot, so this is likely...

Code P0303 cylinder 3 misfire

The symptoms you describe along with the blinking Check Engine Light and P0303 trouble code definitely tell us that you have a misfire in cylinder number 3. Your engine uses a coil on plug system. This means each individual...

How do I lock and unlock the doors from inside?

The doors can be locked or unlocked from inside your vehicle in in two different ways. Each door has a manual vertical lock, which can be pushed down to lock, or pulled up to unlock. For the rear doors,...

Car accelerating on its own

Hi. The first thing I would look towards is a problematic accelerator cable. I would recommend checking the accelerator cable for defects, kinks, and miss adjustments. If that is found to be the problem, have the accelerator cable replaced by...

Related articles

The Best Used Cars to Buy If You're a General Contractor
If If you're a general contractor, you probably aren’t in the market for a used car. More likely, you’re looking for a pickup truck, because you need to haul equipment and supplies to various job sites. Most contractors will likely...
2012 Ford Mustang vs. 2012 Dodge Charger: Which One Should I Buy?
Technically these two vehicles have wildly different classifications: compact for the Ford Mustang and large car for the Dodge Charger. However, who would consider either one anything other than a muscle car? These cars are meant for speed, fun, and...
The Top 5 Selling Cars in Arizona in 2012
Depending Depending on where you live in Arizona, the weather is either arid or there may be periods of heavy snow – such as in the mountain areas. The vehicles that have been popular in previous years for the area,...