Q: Car runs rough in drive but run smooth in neutral

asked by on January 12, 2017

Why does my car run rough in drive and smooth in neutral

My car has 16700 miles.
My car has an automatic transmission.

Hi There, It sounds like you may have a faulty MAP sensor as the car responds to putting it in gear or otherwise putting the motor under load. 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 (i.e. when you put it in drive), 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. 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

I went to get gas and when I opened my gas cap there was a red puddle of liquid at the entrance to the gas tank.

I can't think of another explanation. That kind of vandalism is not uncommon. You need to have a sample taken from the fuel and checked for contaminants. It might be necessary to drain the fuel tank and clean it out....

Toyota Corolla misfire on number two.

In many cases, misfires can be diagnosed by swapping components from the missing cylinder with the components of a functioning cylinder. Then you check the scanner to see if the misfire moves. It can be time consuming, but most auto...

Slight misfire

Hi there. From the description you have given, the slight misfire could be caused by worn or fouled spark plugs. The slight misfire is apparently not being recognized by the vehicle's computer (the check engine light would flash and then...

Bad torque converter?

Hello. A vehicle that stalls when put into gear can be caused by a few different things. A few common causes are engine performance or transmission issues. If the engine encounters performance issues such as fuel problems, or a fault...

My dodge charger 2010 sxt keeps locking itself making the honk noise. How can I turn this annoying sound off? Please help.!

Sometimes a faulty battery can cause this. Have the battery load tested to determine its condition. Other causes of horn malfunctions are electrical shorts that occur intermittently as well as possible software glitches in the body control module and/or security...

Hood will not open

It seems the accident may have damaged the mechanical linkage and has caused it to bind. I would recommend heading to a collision center that can assist you and release the connection. As the vehicle is already damaged, releasing the...

Engine swap. And it doesn't start!! 2005 Dodge Ram 1500

Hello - engine swaps always seem harder than they should be! In your case, a "no start" condition, being skeptical of the crankshaft position sensor (CPS) is a good idea, and easy to check. If there is no spark at...

Hard shake a minute apart while car is in idle.

This could very well be the compressor coming on. Your A/C compressor puts a very heavy load on the motor, especially a smaller and lower horsepower motor like the 1.8L in your Honda Civic. When the compressor kicks on...

Oxygen sensor

The code P0132 is for the O2 sensor in the rear manifold of the engine. The code is for a short to power and should be checked to see if the harness is shorted. You should not have the sensor...

Related articles

The Best Used Cars to Buy If You’re a Vet
The The best car for a vet to own largely depends on the type of practice he or she has. Large animal vets are probably going to want something that delivers a fair bit of power, and possibly even towing...
The Best Used Cars to Buy If You're a Gardener or Landscape Architect
Gardeners Gardeners and landscape architects need to haul around quite a bit of gear. As a gardener, chances are you will need to transport a variety of mowing equipment, along with smaller implements. You may also need to move shrubs,...
A Buyer’s Guide to the 2010 Dodge Viper
2010 2010 was the last production year for the Dodge Viper before it took an extended leave of absence from the automaker’s lineup. It would debut once more in 2013. The 2010 Dodge Viper is a two-seat roadster (convertible) and...