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Psychic Mechanic
Psychic Mechanic, ASE Certified Technician
Category: Car
Satisfied Customers: 1426
Experience:  ASE Master L1 20 years experience
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2001 Infiniti QX4: misfire on cylinder 4. Had #4 coil..spark plugs

Customer Question

I have a 2001 Infiniti QX4 that has been in and out of the garage and after spending many $$$$$$$$$$ has the same problem. Consult diagnosis indicated P0304, misfire on cylinder 4. Had #4 coil installed, fuel injectors cleaned, spark plugs replaced etc, etc. The problem is, there is still an ignition misfire the vehicle hesitates while driving (doesn't matter what speed 30 mph on a local road or 65 on the interstate). The check engine light is still on. If I disengage the overdrive the misfire stops. Any suggestions? I'm desperately looking for HELP!!!!!!
Submitted: 6 years ago.
Category: Car
Expert:  PAVLIN replied 6 years ago.
Chat Conversation Started
PAVLIN :

Hi,

PAVLIN :

make sure that cylinder has compression first, then if it is ok, make sure coil and injector wiring is ok-no open circuits or shorts to ground or power, if everything checks -

PAVLIN :

OK replace PCM

JACUSTOMER-k567xacl- :

To start with I know nothing about cars other than if it has gas and I turn the key it should run. That's why I count on my mechanic and according to the garagethe compression tests were done and everyting is ok. What is a pcm?

Expert:  Psychic Mechanic replied 6 years ago.
Hello Thank you for using JustAnswer.com

I am an Infiniti Master tech. I see problems like this all the time. Have you had the code scanned to see if it is the same cylinder? In my experience when one coil goes the rest are not far behind. I usually recommend all 6 coils. If you go to AutoZone you can get your code read for free. Let me know what you find.