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Engine codes p0305 and p0306 misfires diagnosed?

P0305 and p0306 engine misfires on my 2006 lexus is250. Check engine, vsc and traction control lights are illuminated along with problems accelerating while driving the car. The coil pack on cylinder 5 was replaced and the problem persists. Help pls

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Ty Gordon, The car possibly is going into limp mode because of misfire, for this reason take care of the misfires first. The P0305 /P0306 code, cylinder 5/6 is misfiring or is randomly misfiring. Maybe check for vacuum leaks as a first step, with engine running(spray starter fluid around the intake manifold base, throttle body, injectors, vacuum lines etc.) and listen for a change in how the engine is running, then check/change the plugs. You could switch the 5 or 6 coils around to different cyl. to see if misfire switches to a different cylinder, telling you coil is probably bad.

Possible causes are: Faulty spark plug cylinder 5/6, Clogged or faulty fuel injector 5/6, Faulty ignition coil 5/6, Fuel injector 5/6 harness is open or shorted, Fuel injector 5/6 circuit poor electrical connection, Ignition coil 5/6 plug/harness is open or shorted,Ignition coil 5/6 circuit plug/poor electrical connection, bad valves, low compression cylinder 5/6, fuel pressure low, Intake air leak,etc,etc. links below give a little more info on misfire codes and how to diagnose. If not comfortable working on your vehicle have a good technician have a look diagnose and estimate repair. Good luck.

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