Toyota Corolla Engine Misfire – What Could Be the Cause?

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Toyota Corolla Engine Misfire – What Could Be the Cause?

Hi everyone,

I’ve been experiencing occasional engine misfires in my Toyota Corolla, especially when accelerating o r idling. There are no check engine lights, but I can feel the car hesitating. I recently changed the spark plugs and ignition coils, but the problem persists.

Has anyone else dealt with engine misfires in their Corolla? What other possible causes should I check?

Looking forward to your advice!

Sandeep asked on 29 Jan 2025 14:38:23 pm

1 Answer

20 views |

Car Mechanic Expert - on 29 Jan 2025 14:46:09 pm

Hey!

I understand how frustrating engine misfires can be, especially when youve already replaced the spark plugs and ignition coils. Since the issue persists, there are a few other potential causes you might want to check:

Fuel System Issues – A clogged fuel injector o r a weak fuel pump can cause misfires, particularly during acceleration. Running a fuel injector cleaner o r checking fuel pressure might help diagnose the issue.

Vacuum Leaks – A leak in the intake manifold o r vacuum hoses can disrupt the air-fuel mixture, leading to misfires. You can try a simple check by listening for hissing sounds near the engine o r using a smoke test.

Dirty o r Faulty Mass Airflow MAF Sensor – If the MAF sensor is dirty o r malfunctioning, it can cause hesitation and misfires. Try cleaning it with MAF sensor cleaner and see if that improves performance.

EGR Valve Issues – A stuck o r faulty Exhaust Gas Recirculation EGR valve can cause rough idling and hesitation. Cleaning o r replacing it might resolve the issue.

Bad Engine o r Transmission Mounts – Sometimes, a rough idle o r hesitation feels like a misfire but is actually due to worn engine o r transmission mounts.

Even though there’s no check engine light, it might still be worth scanning for any stored trouble codes using an OBD-II scanner. Some intermittent issues might not trigger a warning light but could still leave behind useful diagnostic codes.

Let us know if you find anything! Hope you get the issue sorted out soon! 🚗💨