Q: it idles fines in park, but cuts out in gear.

asked by on December 25, 2016

i started my car and it idled fine but when i put it in gear it acted like it wanted to die, it was cutting out and running very rough, so I put it back in park and it quit and then I put it back in gear and it started it again but worse.

My car has 225000 miles.
My car has an automatic transmission.

It sounds like you may have a faulty MAP sensor. 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 (spark knock) 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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

When my truck is in park you barely turn the steering wheel and a serious vibration occurs.
The power steering pump on most vehicles have a pressure relief valve that will cause the problem you are having. Since you did not list the vehicle or year for the car you have, I cannot go any more in...
Car jerks at over 60 mph while shifting from third to fourth gear
Hello. Most of the time, when this vehicle starts doing this in higher gears it is because the transmission is failing internally. The clutch packs begin to fail and slip and this occurs. It can also be a pressure issue...
The cooling fan won't turn and car over heats
The radiator fan consists of the fan motor powered by the fan relay in the engine compartment relay box. The cooling fan relay is controlled by the fan control module behind the glove box. This control module will turn on...
Why is something in the hood of my car ticking?
You need to check the oil level to see how low you are on oil (https://www.yourmechanic.com/services/oil-level-is-low-inspection). You may not have added enough oil. If you are not sure then go to a full service station or have a technician, like...
A noise specific to the right front end
Hi there. Your Lincoln Town Car has something in the front related to the suspension called a sway bar. When you drive over bumps on potholes this helps to support the suspension as it does its job dampening the bump....
A lot of smoke coming from the car. What's the issue?
Hi, thanks for writing in. If you have smoke being emitted from your vehicle, it is likely due to a fluid that is leaking (https://www.yourmechanic.com/article/how-to-find-the-source-of-an-oil-leak-by-ed-ruelas) and landing onto a hot surface such as the exhaust. Typically when smoke comes from...
Damaged ambient air temperature sensor
The short answer is yes, but only slightly. The ambient air temperature sensor provides information for the engine management system to make the correct fuel air mixture for the local temperature. If the sensor is damaged, it usually causes a...
What causes oil leak between head and block and whitish blue smoke from exhaust plus milky oil
This is a common sign of a blown cylinder head gasket. In between the cylinder head and block is a thick gasket that seals off the combustion chamber and maintains separation of the oil and water passages through the cylinder...
I have a 2007 Chrysler Sebring. The gear shaft is in park but the dash shows it in Drive. The car will not start now. The red ligh
The engine might not start because the neutral start safety switch "thinks" the car is in drive. There is a problem with the selector, the switch and/or the shift/gear selector cable adjustment. To figure out which of the three, the...

Related articles

A Buyer’s Guide to the 2012 Toyota Tundra
While While Toyota hasn’t been in the business of manufacturing larger pickup trucks as long as the likes of Ford, Chevy, and Dodge, the Tundra is most definitely a force to be reckoned with. This full-sized pickup has comparable payload,...
Top Automotive News & Stories: September 24-September 30
Angry Civic Type R, 350 special edition Ferraris, Infiniti variable compression tech, Mercedes' electric future, and more.
Top 10 Best-Selling Cars of 2016
Ford F-series pickup trucks, Toyota Camry, and Honda Civic are some of the best-selling cars of 2016 and all deliver on reliability and efficiency.