tjack

If you hear a single clunk when you reach approximately 10 mph after a power cycling, it may be the ABS performing a startup. I bought a 2004 Frontier about 6 weeks ago. I noticed the noise after a couple of weeks. I took it back to the dealer. The service advisor didn't know what the problem was so he wrote it up. The noise was so predictable that I thought it must be normal so I searched several website including this one. I took it back to the dealer and talked to their lead technician. After we drove the truck he looked on his computer at a Nissan program called "Asist" (yes it's really spelled like that). The program had a similar symptom description and said that it was caused by the ABS performing a startup or calibration. It said that some vehicles do this at startup and some do it at 5 mph. Mine did it at 10 mph per my speedometer. I also drove another new one and it did the same thing. The noise is subtle and you can even feel it slightly in the floorboard. It is a distinctive single clunk. I live on a gravel road and I would never have noticed it except I park on a paved parking lot at work and could hear it there. I suggest that you take it to the dealer and mention this just in case you have something more serious going on. In my case it turned out to be something normal. Hope this helps someone.