2000 Nissan Xterra Skips and Bucks

by Jim
(Grifton, NC USA)

My 2000 Nissan Xterra has a bad misfire when it gets warm. While it is cold it seems to be O.K. but gets progressively worse as its warming up. There is no service engine soon light on. When it's running and hot it bucks badly. There is a P0325 code pending which I thought was a result of the bucking and the misfiring. Even after I clear the codes the 0325 code will come back, I can't see the knock sensor causing the bucking and skipping. The truck has 145,000 miles on it and has been well cared for. I installed a new set of spark plug wires thinking it might be a bad wire. A friend told me his Nissan pick up truck was doing the same thing and said that I needed to replace the distributor. The engine is a 3.3 V6 with an automatic trans and 4x4. Thanks for any help.
Jim

Steve Says,

The computer uses the knock sensor to tell when your engine knocks. If it does then the computer will change ignition timing to make it so it does not knock. If the knock sensor was malfunctioning and sending the wrong signal to the computer then the computer might be drastically changing the timing which could account for your driveability problems.

Code P0325 will not ever go away even if you turn the light off because it is a constant fault. The computer will test the knock sensor circuit often and will set code P0325 until the problem gets fixed.

The computer will not necessarily turn the check engine light on with this code because it does not know that the signal is bad. It simply thinks that there is a knock because of what the sensor is telling it.

Most likely this is just a bad sensor, but it could also be a problem with the wiring for the sensor circuit.

I hope this has helped.