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Knocking and gas

(1998 Nissan Altima)
in Portland, OR on December 22, 2010
I took my car and had the codes pulled for the check engine light and I was told it was the knock sensor. But one day the car was fine and the next day I would try to accelerate and it would slowly go then out of no where it was like going over a speed bump and the car would speed up to what it should have been doing for the amount of pressure I was putting on the gas pedal. I don't know anything about cars. What could this be?
Displaying 2 answers & 2 comments
Popular Answer
on December 22, 2010
was there any other code besides the knock sensor?? nissan has an issue with ghost code for the knock sensor. it usally accompanies another code.

on December 22, 2010
No there was only the one code.

on December 22, 2010
ok, then there may be an issue. the sensor listens to harmonics in the motor and when it detects knocking, it retards the timing 4 degrees up to 4 times to try to eliminate the noise. if it cannot get rid of the noise, it flags a code for help. you may want to have a shop check it for you to confirm the issue.

of Tom's Auto Clinic on December 22, 2010
The engine computer uses the knock sensor signal to adjust engine timing. The knock sensor may or may not effect how the engine runs on your Nissan. Most discount part stores will check your code however that may not be the problem at all. There are many things that would cause the computer to list a knock sensor code, many causes that have nothing to do with the sensor itself. I would recommend you have the problem analyzed by a professional technician.
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