Skip the auto shop - Our mechanics make house calls

Q: Dosen't always start

asked by on

it doesn't always start
My car has an automatic transmission.

A: Hi there. There are a lot of things that ca...

Hi there. There are a lot of things that can cause this. It really depends on what the car is doing when you are trying to start it. If the engine cranks and it just does not start then most of the time it is a bad crankshaft position sensor. I usually use a scan tool to monitor the sensor signal to see if it is correct when the issue is occurring. If it is not then I replace the sensor.

It can also be a number of other things including a fuel system issue. If the car does nothing when you try starting it then most of the time it is either a bad connection at the battery or a failing starter. It can also be a failing ignition switch or a clutch switch if the vehicle has a manual transmission.

Some electrical diagnostics would need to be done to find out which one it is. If you need to have this looked at, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose your starting issue firsthand.

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・Save up to 30%

Get a quote

What others are asking

Q: Stalls while applying throttle. Already changed two warm up regulators

Hello. I think you may have a problem with the cold start valve not dumping the proper amount of fuel to allow the car to start and remain running on a cold start. The distributor should be checked as well...

Q: Truck turns off when I press the clutch to put in second gear to turn

Hello. Your engine is stalling when you let off the gas and this can be from an engine vacuum leak, idle air control valve, or just the engine computer that has not relearned the idle yet. Try to let...

Q: Temperature guage reading high when idle

With your symptoms, the vehicles water pump is a likely culprit. With a working coolant thermostat and radiator fans, the next parts to suspect are a fluid leak or malfunctioning water pump. If the vehicle has been overheating, I will...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.