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Q: I have a 1997 nissan maxima that has a misfire code of p0300 and p0302.

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I checked the coil packs and harness connector with a multi-meter and all are getting a reading. I also started the car and took off each fuel injector connector and every cylinder gives a drop in rpm. I removed all the spark plugs and noticed that cylinder #2 is wet with unburnt fuel and all the others are dry. The car was sitting for about 3 weeks and I barely started to drive it. What could be my problem? Car is running rough and shaking at a complete stop. Should I waste my money on fuel injector cleaner and spray out the throttle body with cleaner to see if it helps any? Before I did any of the work I mentioned above, I replaced cylinder #3 coil pack because it was too short and it was arcing, but now its misfiring on #2. Please help.

My car has 243500 miles.
My car has a manual transmission.

It’s common to find the source of a misfire in the ignition system. Checking the coils with an Ohmmeter doesn’t really tell you much though. When I diagnose a misfire, sometimes I find it helpful to swap the coils and plugs to another cylinder and check to see if the misfire codes move. That way you can isolate the fault without buying a bunch of parts that you don’t need. But if you had a coil that was arcing, it’s possible there has been some damage to the ignition primary, and you will need a scope to diagnose that. I don’t really recommend the Fuel injector cleaner. It’s a good maintenance procedure, but I’ve never actually cured a misfire with it. If you want help sorting this out, you can contact Your Mechanic to have a technician come out to your home or office to check out you misfire and recommend a solution.

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