Hello, I would have to suggest getting it replaced. As you stated, if you are trying to pull out in traffic and it stops, the repair cost is worth the safet factor. Go ahead and have it replaced as soon as you can. Thanks
Should I take it to a Nissan dealer to have it replaced?
Yes, that is the only place that has a new and not rebuilt part for this application.
Will they replace if without being able to verfiy the code? What is the approixmate cost?
You will have to bring paper work from your mechanic to them. If it is only the throttle position ssensor, and there is no damage or wear on the throttlebody shaft, the sensor is about $150 plus an hour labor. If the throttlebody assembly has to be replaced, it is about $625 plus an hour labor.