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Q: Misfire on cylinder 3

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When the RPMS raise past a certain level, usually around 2500, or when accelerating quickly or to highway speeds, the vehicle throws a code and begins running poorly. Code is showing a misfire on cylinder 3. I've changed the ignition coils, spark plugs, and inspected/cleaned all fuel injectors. And based on visual inspection there seems to be no leaking around the intake manifold. However the issue still persists. Any suggestions on what else might cause this?

My car has 110000 miles.
My car has an automatic transmission.

A: Hi there. Are there any other codes stored ...

Hi there. Are there any other codes stored with the misfire code? Any additional codes and data may help us in determining the concern more accurately. You may still have an injector problem as the number 3 injector could be leaking fuel or restricting fuel. There could also be an internal mechanical issue at hand. Swap the new coil in cylinder 3 with another cylinder; make sure to mark the coil, and check to see if the misfire moves cylinders. If it moves, then the coil is at fault; even a new coil can be faulty. If it doesn't move, then move the spark plug and recheck. If it moves, then the spark plug is faulty. If it is possible to be done relatively easily, swap the injector for cylinder 3 and another; check to see if the misfire moves. If there is no change, then the concern could be either a computer or an internal mechanical malfunction, such as a failed driver or low compression. I strongly suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several technicians that can assist you with a check engine light inspection.

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