2004 XTerra poor idle and ignition firing
 

I have a 2004 XTerra, 55,000 miles, got a bad tank of gas and fouled my plugs, which I replaced, and used several containers of fuel injector cleaner. Car still starts and idles poorly, and service engine light still goes on and off intermittently. Diagnostic computer indicates misfire on #6 plug and bad knock sensor.

#6 plug is very hard to get to (between firewall and rear of engine - can't see it at all, done by feel alone w/ two socket extenders and a swivel joint). Sensor is real expensive and under intake manifold, which has to be removed - 4 hours +/- of work. Knock sensors are many times NOT the problem either.

Are there any other possible things to check for before replacing the sensor? And is there an alternate (cheaper) sensor that can be used from earlier Nissan model that will work? (I'm sure there is, the trick is just knowing which one)

those are might be rare to find but I know there are some.

Thanks
 

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