# knock sensor and e.g.r control valve



## y_yavuz1979 (Nov 10, 2005)

hi, i am yalcin.i have a 1995 nissan altima. my car's engine check light is on. and one of mechanics checked my car and told me "knock sensor" and e.g.r control valve must change. which cost about usd 550 (insallation include)

what do knock sensor and e.g.r valve do ? if i don't change them what can be happen ? 

also my car's gas consumption is realy huge, how can i decrease that? i read some forums related that subject and one of them wrote, to change oxygen sensor.

is the oxygen sensor is same with the knock sensor or not? how much does oxygen sensor cost?

thanks for your time and help.


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## 2000SE (Oct 28, 2002)

The oxygen sensor is not the knock sensor.

Buy and replace the sensors yourself. They are not cheap but you can shop around online(parts.com, autozone.com, napaonline.com, partsamerica.com) for the best price. 

Don't expect MPG to improve until all failed components are fixed. Everything works together and the ECU won't be happy with broken parts.


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## y_yavuz1979 (Nov 10, 2005)

thanks for your reply, i will replace the sensors and fix the other problems,
also buying some sensors and selenoid valves (used ones)from a dealer can be a problem for future. or can i buy new sensors and valves from an dealer?

thanks for your time and help.


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