Do I need to fix this? EGR/Knock Sensor

[Penguins50]

I took my 96 G20 to the mechanic to diagnose the check engine light. The codes were P0325 - Knock Sensor Circuit and P0400 - EGR System Circuit.

To replace both of these the cost would be ~1800. To take care of only the EGR problem would be ~500.

The car has 120k miles and I estimate is only worth about $1000 so I hesitate to put a lot more money into it. My understanding is that these problems would affect my gas consumption and engine efficiency but I have not noticed any problems while driving or reduced gas mileage. Do I need to get these repairs done? I only drive about 5000 miles a year now.

The mechanic mentioned that if I don't fix it the car could eventually stall. How likely is this and would I risk damaging other parts of the car? Or could I always just get the same things fixed when (if) that happened?

Thanks very much for your replies. I look forward to any comments.

[NJ 666]

I would only fix the EGR system. The knock sensor code will NOT turn on the CEL but it does store a code. I see a lot of the lder cars set this code but it seems only the J30 is affected by it. What did they want to change for $500? Usually the only problem with them is carbon build up,control solenoid or a vacuum line

[dmp316]

I took my 96 G20 to the mechanic to diagnose the check engine light. The codes were P0325 - Knock Sensor Circuit and P0400 - EGR System Circuit.

To replace both of these the cost would be ~1800. To take care of only the EGR problem would be ~500.

The car has 120k miles and I estimate is only worth about $1000 so I hesitate to put a lot more money into it. My understanding is that these problems would affect my gas consumption and engine efficiency but I have not noticed any problems while driving or reduced gas mileage. Do I need to get these repairs done? I only drive about 5000 miles a year now.

The mechanic mentioned that if I don't fix it the car could eventually stall. How likely is this and would I risk damaging other parts of the car? Or could I always just get the same things fixed when (if) that happened?

Thanks very much for your replies. I look forward to any comments.

These are easy fixes. Your knock sensor if going bad will throw your timing off making it hard to drive. EGR sensor will f up with your idle.

That mechanic is full of sh**. that is a rip off.......1800 f*** that . The both parts will not cost you more than 300 bucks. Go here and order both of them and install them yourself. http://gspec.com/

Knock sensor is a b**** to get to. It is behind the engine block. So you have to jack the car high to get to it

[NJ 666]

A P0400 is no or low EGR flow and that won't do anything to the idle. On MOST Nissans a "bad" knock sensor doesn't really affect the performance. If you scan the timing you will see not too much is pulled out. The ECM logic is that if there is a defective sensor that it can't be "trusted". Also, remember that with OBD-II any failure that will increase emissions must turn on the CEL and severely reduced timing will do that. The only model(at least on the Infiniti side) that a failed KS will noticeable reduce power output was the J30. Most customers are unaware that their cars ever have a KS code.

But there is always the exception to the rule,