Ok i pulled my codes today and got the Knock sensor and the EGR fault codes. They told me that the EGR is definetely at fault and it might cause the knock sensor to throw codes. WHat should i do? My car really lacks power right now, bad gas mileage and hessitates a lot, rpms go up and down (and no i dont have a sound system installed). I bought the knock sensor from the dealer. Should i clean out the EGR first or should i change the knock sensor at the same time?

 

Your best bet would be to take care of the EGR problem first. Once that is done, reset the ECM and drive for awhile. Check to see if you are still getting any codes using a scanner or putting the ECM into diagnostic mode. Remember, the knock sensor alone may not turn on the MIL but you can still have the code stored.

 

Check page 2 on how to's (troulbleshooting EGR problems)
my problem was resolved by replacing EGR solenoid valve.

 

also check this thread (EGR RELATED)
http://forums.maxima.org/showthread.php?t=357902

 

Who are "they?"

 

Hopefully not the stealership...

 

autozone!
Can the car's lack of power be from the egr?

 

It could be. Depends on what's wrong.

EGR is used to lower your combustion chamber temperatures. Partly this is done
to reduce pollution (NOx). But it also allows the engine to run a more advanced ignition timing without knocking. If the engine senses knocking due to malfunctioning EGR, it is going to pull timing advance and your engine will feel sluggish. Bad EGR may also tend to give you poor driveability (stumbling, hesitation, etc).

 

As soon as there is an KS error code, doesn't the engine go into a "safe" (retarded timing) mode...? That would explain the power loss. A bad EGR can decrease mileage, have rough idle, among other things.....I have never replaced it on the MAX, but it sure doesn't look like it would be any fun.