Q: Codes p0300, p0304

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The car runs fine but the codes are present Changed wires, spark plugs, coil pack The engine light is not blinking Thinking of changing fuel injectors, fuel filter but I'm not sure if this will fix the problem Help plzz.

My car has 139000 miles.
My car has an automatic transmission.

Hi there. As you already know, replacing components without diagnoses can be expensive and time consuming without resolution. A faulty fuel injector(s) is a possibility but, the P0304 (#4 cylinder misfire) may be affecting other cylinders causing the P0300 (random cylinder misfire) code to set. This would indicate, a compression test and cylinder leakage test is in order, especially with the check engine light not flashing. A valve train related misfire (cylinder head valve not sealing) could be overcome with increased engine rpm (revolutions per minutes). I recommend having your vehicle’s check engine light be diagnosed and repaired by a certified technician, such as one from YourMechanic.

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