What causes this error - po303 code

The other night while driving on the interstate, I noticed my car behaving strangely. Initially, the engine light came on for about 10 seconds and then turned off. However, soon after, the engine stalled while I was still driving. I managed to get the car to my hotel, albeit it was running poorly. Whenever the engine dropped below 2000 rpm, it would threaten to stall again.

I bought a code reader and it indicated a misfire in cylinder 3. I’ve already replaced the spark plug and coil, but unfortunately, that didn’t resolve the issue. My dad suggested it might be a problem with the fuel injector.

I have an appointment scheduled with Hyundai on Wednesday to have it inspected, but I’m concerned about potentially being overcharged. Any advice or insights would be greatly appreciated. The car is a 2015 Hyundai Sonata SE with 146,000 miles.

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It sounds like you’re navigating a frustrating situation with your Hyundai Sonata experiencing a misfire in cylinder 3 despite replacing the spark plug and coil. Your dad’s suggestion regarding a potential fuel injector issue is plausible, as faulty injectors can cause similar symptoms. Given your upcoming appointment with Hyundai for inspection, it’s wise to let their technicians diagnose the problem thoroughly, leveraging their expertise and diagnostic tools specific to your car model. To avoid potential overcharging, request a detailed estimate upfront, authorize diagnostics first before any repairs, and inquire about any applicable warranties or recalls that could offset costs. Keeping open communication with the service team and understanding the diagnosis and repair options they propose will help ensure clarity and possibly reduce expenses.

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I agree with your dad.
Try to move the fuel injectors around next and then do a compression test. Hope that works out.

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The error code “P0303” indicates a misfire detected in cylinder 3 of the engine, P0303 is basically caused by problems with the ignition system, faulty fuel injectors, or damage to the engine.

The error code “P0303” indicates a misfire detected in cylinder 3 of the engine, P0303 is caused by problems with the ignition system, faulty fuel injectors, or damage to the engine.
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