I replaced the coolant temperature sensor less than a year ago, and have gone through and cleaned all the connectors and used some electric grease to keep the contacts from corroding. What is the other temperature sensor? Isn't the AFM responsible for sensing the temperature of the air coming in through the intake? I know the egr has a temperature sensor, but again, I don't have any codes coming up. I'm not 100% sure my timing tensioner is bad or responsible for the noise... I guess it could be a lifter, but it's weird that some mornings it will make noise and some mornings it won't. I haven't gotten into the timing cover to investigate because it's a royal pain, but the timing was done approximately 15k miles ago and I trust my shop to have done it right... plus I provided them with my nissan service manual.