Need some advice on my 2010 Hyundai Accents misfire

General
1

I’ve been working on this car for more than two weeks, and despite changing the coil packs, plugs, injector, and intake gasket today, it continues to misfire in the second cylinder. It appears to be a little better, but after a few minutes it begins to tremble. If I switch on the air conditioning, the engine will become more stressed and will shut down. The o2 sensor bank 1 sensor 2 broke off and became lodged in the port; I have already thought of a solution, but I still need to stop the misfire. Should I tighten the intake bolts once more after operating it for a while?

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2

You ave really put in a lot of work on this! Here are some things to check: Look for any vacuum leaks, as even a small one can cause misfires. Run a compression test on the second cylinder to spot any internal issues. Make sure the fuel injector is working properly, as even new ones can fail. Replace the broken O2 sensor, as it might be affecting the engine’s performance. Also, check the ignition coil and spark plug, and retighten the intake bolts after the engine has run for a bit.

3

The issue is indeed challenging. Given the extensive work you’ve already undertaken, it’s time to explore deeper potential causes.

Potential Issues:

  • Catalytic Converter: A clogged or damaged catalytic converter can lead to misfires and increased engine strain.
  • Fuel Pump: A malfunctioning fuel pump might not provide adequate fuel pressure.
  • Timing Belt or Chain: Problems with the timing system can cause misfires and serious engine damage.
  • Compression Issues: Low compression in cylinder 2 could indicate a mechanical issue.
  • Electrical Problems: Faulty wiring or sensors may disrupt engine performance.

Next Steps:

  • Check Engine Light: If the Check Engine Light is on, read the codes to pinpoint potential problems.
  • Compression Test: Perform a compression test to check for mechanical issues in cylinder 2.
  • Fuel System Check: Assess fuel pressure and injector performance.
  • Exhaust System Inspection: Inspect the exhaust system for blockages or damage.
  • Professional Diagnosis: If you’ve explored these options without resolution, consult a mechanic for a professional diagnosis.

Tightening the intake bolts may not address the core issue. It’s crucial to identify and resolve the underlying cause of the misfire to prevent further damage.