Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that when you start your car, some of the engine's cylinders aren't working right. It's like trying to run with one shoe untied.
The P1340 code indicates that the engine control module (ECM) has detected multiple misfires in the engine cylinders during the startup phase.
The P1340 code is triggered when the ECM detects that two or more cylinders are misfiring during the engine start-up phase. This can be due to various issues such as ignition system problems, fuel delivery issues, or mechanical engine faults.
• Rough engine start
• Poor engine performance
• Check Engine Light illuminated
• Faulty spark plugs or ignition coils
• Fuel delivery issues such as a clogged fuel injector
• Vacuum leaks or air intake issues
ECM: Engine Control Module, the computer that controls engine functions.
Misfire: When a cylinder in the engine fails to ignite the air/fuel mixture properly.
• Use an OBD-II scanner to confirm the code.
• Inspect spark plugs and ignition coils for wear or damage.
• Check fuel injectors and fuel pressure.
• Replace faulty spark plugs or ignition coils.
• Clean or replace clogged fuel injectors.
• Repair any vacuum leaks.
• OBD-II scanner
• Spark plug socket
• Fuel pressure gauge
$150 - $500
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly replace spark plugs and ignition components.
• Use high-quality fuel.
• Perform regular engine maintenance checks.
Engine Performance
• Do not ignore the Check Engine Light.
• Have a professional diagnose the issue if you're unsure.
• Keep up with regular vehicle maintenance.
Check with your vehicle manufacturer for warranty coverage on engine components.
This code has been commonly reported in vehicles with higher mileage or those that have not been regularly maintained.
Moderate – It's important to address this issue soon to avoid further engine damage.
Driving with a misfiring engine can lead to increased emissions and potential safety hazards.
• Engine must be cold and started from rest.
• Ensure the vehicle is in a safe environment for testing.
The ignition components are typically located on top of the engine, connected to the spark plugs.
Q: Can I drive my car with a P1340 code?
A: It's not recommended to drive with this code as it can lead to further engine damage.
Q: What happens if I ignore a P1340 code?
A: Ignoring this code can result in poor engine performance and potentially costly repairs.
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Fitment Required · Vehicle-fitment part
Commonly relevant for misfire, ignition-efficiency, and some drivability-related repairs.
Misfire and ignition-related faults commonly involve spark plugs as part of the repair path.
Check the correct plug type, gap, and engine application for your vehicle.
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Fitment Required · Vehicle-fitment part
Relevant when the fault points toward ignition-coil performance or cylinder-specific ignition issues.
Some ignition faults involve coil performance or cylinder-specific coil problems.
Match the coil to your engine and confirm the failed component before ordering.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.