I am having some problems starting my car in this cold weather. The starter rotates but I need to step on the gas and keep cranking before it finally starts. A few days ago, my check engone light came on. I diagnosed it and found three error codes:

0304 - Knock Sensor
0407 - Crankshaft Position Sensor (Reference)
0707 - Rear Heated Oxygen Sensor

My car stutters a little bit sometimes during acceleration. After searching through this forum. I found out that this may be because of the knock sensor. And will replacing the rear oxygen sensor eliminate the hard starts? I am thinking of replacing the oxygen sensor first, and see how the car runs before replacing the other 2 sensors. The lowest price I found for the oxygen sensor is about 120 bucks from JeromeNissan. Is that a fair price?
If someone out there have experienced the same problems that I have and is willing to give me some edvice, I will greatly appreciate it. Thanks!

 

I had the exact same problem, I would recommend replacing the crankshaft position sensor first and then the Oxygen sensor. With your engine running lean "i think" could have triggered a fault code with the knock sensor so there may be nothing wrong with it. Give it a try and let us know your results.

 

thanks for you advice....i will try changing the crankshaft position sensor first

 

if i were you, i would try cleaning the crankshaft sensor first...it gets clogged up, u know...

o2 sensor, cheap.
crankshaft sensor expensive.