Why does my car run bad when it warms up?

It may be getting too much fuel once it’s warmed up. An engine needs more fuel when it’s cold than it does when it’s warm. A choke plate closes-off the air going into the carb which makes the fuel mixture really rich so it can run. Less air = more fuel.

What causes a car to stall when you put it in gear?

An automatic car can stall when put into gear for countless reasons. It could be a result of a faulty coolant sensor, bad alternator, empty fuel tank, bad fuel pump, leaking vacuum when the filter is blocked, etc.

What causes rough idle when cold?

While there are many potential causes for shaky cold-weather performance, two of the most common are failing engine temperature sensors and bad thermostats. In both cases, the underlying reason for a rough idle is an overly rich air to fuel mixture.

What causes a carburetor to not idle?

Most carburetors have a separate idle circuit and, compared to today’s fuel-injected engines which are pre-set, the idle speed and mixture can actually be adjusted. Often, dirt in the idle circuit can cause a no-idle situation, where the engine will run well at road speed.

What happens when carburetor is bad?

The carburetor is the main component responsible for metering and delivering the air fuel mixture required for the engine to run. A bad carburetor may result in an engine with sluggish acceleration, and a noticeable reduction in power and fuel efficiency.

Can bad transmission fluid cause rough idle?

If your transmission fluid is contaminated by dirt or other material, then its response will be very laggy and sluggish. Once that starts happening, your gear shifting will cause the gears to change too fast or too slow as you’re driving the vehicle.

Why does my car idle rough in cold weather?

Either way, the cold engine will experience a rough idle in cold weather until the engine reaches the proper operating temperature to run smoothly. The problem with this is that the internal leaks can develop into further driveability problems, like a rough idle when cold being just one of the many issues.

How can you tell if your car is having a rough idle?

You can tell your vehicle is having a rough idle when cold if there is shaking and bouncing sensation in the vehicle, and you feel like the car is vibrating too much while your car is not moving. Although some cases are less severe than others, the rough idle is usually pretty identifiable by both the driver and passengers.

What does smooth idling mean on a car?

Smooth idling indicates that your engine is getting the correct mixture of air and fuel to burn. What is rough idling? If your car’s idle is rough, possibly rising and falling, or struggling to maintain a steady rate of rotation, you may have a problem that needs fixing.

Why does my car stall when I put it in gear?

If the MAP sensor is faulty, this foregoing sequence may explain why the engine dies as you put the vehicle into gear as a load is put on the motor. YourMechanic offers a stalling diagnostic which covers both transmission and engine related faults.