Q: getting a P0021 code. Already change oil and camshaft sensors.What should I do? on 2003 Infiniti G35

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Car is not idling rough or hard starts.
(1) Answer
Are there any unusual noise on start-up that go away after tw or three seconds? How many miles on engine? cam sensor codes can be set due to jumped/worn timing chain components faulty tensioner ...water pump is driven by chain / weak bearings ETC. Scan & get all info possible -before throwing a bunch more parts at it.could also be a cam gear itself ===some of the best info can be had at the dealer---the parts guys at some of these places can be very helpful in figuring out whether or not you have a very common issue or if you should get it checked further ,AGAIN I stress , before putting more unnecessary parts on it.