Q: Dosen't always start

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.