Why My Car Starts Sometimes and Sometimes It Doesn’t & FIXES

Last updated on December 25th, 2023 at 10:54 pm

When your car starts one time but refuses the next, it’s puzzling and annoying. You turn the key, and sometimes it purrs to life, other times—nothing. This strange issue of “My Car Starts Sometimes and Sometimes It Doesn’t” leaves you wondering what’s going on.

Finding out why your car behaves this way involves looking at lots of possible reasons, like problems with electricity, fuel, or the starting system.

Let’s untangle this mystery together, figuring out why your car plays this guessing game. We’ll explain it in a way that’s simple to understand for everyone who owns a car.

Why My Car Starts Sometimes and Sometimes It Doesn’t

Battery Problems

When your car starts acting up, the battery might be the troublemaker. It’s the powerhouse behind starting your ride. A drained battery causes these on-off issues. If you suspect your battery is the culprit, first, check its connections. Clean them up and give jump-starting a shot.

To figure out if it’s really the battery causing the fuss, grab a voltmeter. It measures the battery’s power. A fully charged battery should read at least 12.6 volts. If it’s below that, it might be time for a new one.

If jump-starting doesn’t do the trick, or if your battery’s over three years old or looks damaged, it’s probably time to get a replacement. These steps might help sort out why “My Car Starts Sometimes and Sometimes It Doesn’t.”

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Failing Alternator

When your car behaves like a coin toss—starting sometimes and then deciding not to—it might signal a problem with the alternator. This part charges your car’s battery while the engine runs. So, if it’s not doing its job, your battery might not have enough power to start your car every time.

To check if the alternator is the culprit, use a tester to see if it’s charging correctly. If it’s not, you might need to swap it out for a new one. It’s crucial to fix this soon to dodge situations where you’re stuck with a dead battery and a non-starting car.

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Bad Starter

When your car goes from starting smoothly to being a bit moody about it, the starter might be the culprit. You know, that part that gets the engine going? If it’s acting up, you might hear clicks or grinding noises when you turn the key, or it might just give up entirely.

A mechanic can take a look and figure out if the starter needs fixing or swapping out. All sorts of things can mess up a starter, like worn-out bits or electrical issues. Fixing it fast is key to stopping any more trouble in the engine.

Faulty Fuel Injectors

Sometimes, your car’s picky about starting, and faulty fuel injectors might be the reason behind this unpredictable behavior. These injectors have a vital job—they send fuel into the engine’s combustion chamber. But if they’re acting up, your engine might not get the right amount of fuel to start smoothly every time.

A faulty injector can lead to rough idling, poor fuel efficiency, and even misfires. When an injector gets stuck open, it floods the engine with too much fuel, making it hard to start. And when it’s stuck closed, there’s not enough fuel going in, causing starting troubles.

To figure this out, a mechanic will check these injectors and how they work. If they’re causing the problem, they’ll replace them to get your car starting reliably again.

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Bad Fuel Pump

A bad fuel pump is another possible cause of “my car starts sometimes and sometimes it doesn’t” issue. The fuel pump is responsible for delivering fuel from the gas tank to the engine. If the fuel pump is failing, it may not deliver enough fuel, leading to starting problems.

One of the common signs of a bad fuel pump is difficulty starting the engine or the engine stalling while driving. The fuel pump can also make a whining sound when it’s failing. If you suspect a bad fuel pump, have it inspected by a mechanic.


Clogged or Dirty Fuel Filter

A clogged or dirty fuel filter can also cause the “my car starts sometimes and sometimes it doesn’t” issue. The fuel filter is responsible for filtering out impurities and debris from the fuel before it reaches the engine. Over time, the fuel filter can become clogged with dirt and debris, restricting the flow of fuel to the engine.

If you’re experiencing starting issues with your car, don’t ignore the problem. A clogged or dirty fuel filter can cause more significant problems down the line if left unaddressed. Have it inspected by a mechanic and get it fixed to ensure reliable starting every time.

Spark plugs

Spark plugs are another crucial component that can cause intermittent starting problems in your car. The spark plug is responsible for producing the spark that ignites the fuel and air mixture in the engine’s combustion chamber. If there’s an issue with the spark plugs, the engine may not start consistently, leading to starting problems.

One common issue with spark plugs is fouling, which occurs when the spark plugs become covered in carbon or oil buildup. This can cause the spark to weaken or not occur at all, leading to starting problems.

Another issue that could cause starting problems is worn-out spark plugs. Over time, the spark plug electrode wears out, leading to reduced spark intensity and starting issues. This can occur due to high mileage or improper maintenance.

If you notice your car starting sometimes and sometimes it doesn’t, have your spark plugs inspected to identify and fix the problem.

Ignition Switch

Sure, sometimes when your car acts moody about starting, the culprit might be its ignition switch. This switch is like the car’s electricity boss, sending power to the starter motor when you turn your key. That motor cranks the engine to life.

But if the ignition switch is acting up, your car might refuse to start. It’s usually because of things like worn-out parts or faulty connections inside the switch.

If you suspect the ignition switch is causing your car’s starting drama, ask a professional mechanic for help. Fixing this switch isn’t a DIY project—it’s tricky and can be risky. Letting an expert handle it will keep you and your car safe.

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Crankshaft Position Sensor

The crankshaft position sensor is a critical component in a vehicle’s ignition system. This sensor is responsible for monitoring the position of the crankshaft in real-time and sending this information to the engine control module (ECM).

If the crankshaft positioning sensor is faulty or malfunctioning, it can cause the “my car starts sometimes and sometimes it doesn’t” issue. The sensor may send incorrect or inconsistent signals to the ECM, leading to starting issues and engine misfires.

Signs of a faulty crankshaft positioning sensor include difficulty starting the engine, hesitation during acceleration, and a check engine light. If you suspect a faulty crankshaft positioning sensor, have it inspected and replaced by a mechanic.

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Engine Flywheel

The engine flywheel is a crucial component that helps crank the engine and start your car. If you’re experiencing issues with your car starting sometimes and sometimes it doesn’t, the engine flywheel could be the problem. The flywheel is located between the transmission and the engine and is responsible for rotating the pinion gear to crank the engine.

One issue that could cause your car to have starting issues is a damaged or missing flywheel teeth. If there’s damage to the teeth, the engine may not turn over consistently, leading to intermittent starting problems. In such cases, you may hear a grinding noise when you try to start the car.

Another issue that could cause your car not to start is a problem with the pulley that drives the alternator or serpentine belt. A damaged pulley could cause the belt to slip, leading to the engine not cranking properly.

It’s important to have a mechanic inspect the engine and identify any underlying issues that may have contributed to the flywheel problems

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Troubleshooting the Problem of My Car Starts Sometimes and Sometimes It Doesn’t

Check the Battery

The most common cause of intermittent starting problems is a weak or dead battery. To solve this problem, start by checking the battery’s charge. If it’s low, recharge it with a battery charger and try starting the car again. If this doesn’t work, check and clean the battery connections, including the terminals and cables, to ensure that they are clean and tight.

A dirty or corroded connection can prevent the battery from providing the necessary current to start the engine. If the battery is old or in poor condition, it may need to be replaced.

Check the Starter

If your battery is in good condition, the starting problem may be due to a faulty starter. If the starter motor, solenoid, or wiring is corroded or damaged, it can prevent the engine from starting.

If you suspect a problem with the starter, have it diagnosed by a qualified mechanic, who can replace any faulty parts as needed.

Bring Your Car to a Repair Shop

If you’ve checked your battery and starter and the problem persists, it’s time to bring your car to a repair shop. The issue could be related to a malfunctioning ignition switch or fuel pump, which will require professional expertise to diagnose and fix.

In some cases, you may need to replace certain components that require regular replacement, such as spark plugs.

Check the Engine

Finally, if all else fails, it may be time to check the engine itself. Do a compression test to check the engine’s performance. If it fails to perform, the engine may be reaching the end of its life span, and it may need to be replaced.

Additionally, you can scan your vehicle for codes with an OBD2 scanner tool to determine whether the coil or fuel injection is causing the intermittent starting issue. The easiest way to diagnose and fix these issues is to bring your vehicle to a qualified mechanic.

FAQs on My Car Starts Sometimes and Sometimes It Doesn’t

Q: How can I tell if it’s the starter or alternator?

A: Try starting your car; if it doesn’t start and there’s a clicking sound, it might be the battery or starter. Check battery connections and tap the starter lightly.

Q: How can I spot a bad starter?

A: Listen for odd grinding or whirring sounds when starting your car.

Q: How do I know if my fuel pump is faulty?

A: Look for issues like trouble starting, strange noises from the fuel tank, sputtering engine, or car surging.


Thanks for reading about why my car starts sometimes and sometimes it doesn’t. It can happen due to a weak battery, a messed-up starter, or a broken ignition switch.

Always notice warning signs and fix problems early to avoid car troubles. Follow these tips and ask a pro mechanic for help if needed. Regular car check-ups keep it reliable. Taking care of your car means it’ll always get you where you need to go, without a hitch.