Posted: Oct 02 2007 at 4:31pm | IP Logged

I did a search and could not find anything directly related, so here it goes.

I have a 2004 Frontier that has a constant engine noise that I would describe as a knock. It is constant, and increases in speed with acceleration. I have only ever used premium fuel in all my vehicles.

The first time I brought it in they said it was a distributor problem and replaced the distributor.  The second time they said it was becuase the oil was low.  The 3rd time (at a different dealership) they said it was normal and that there is even a TSB for this.  The 4th time (original dealership) I am being told that it is normal valve and injector noise.

Anyone have any insight at all. If it truly is normal, then I will put it to rest, but I can't help feeling like I am being told what is convenient for them.

Posted: Oct 03 2007 at 12:23pm | IP Logged

I have the same exact noise in my Frontier that you are describing and when i took it to the dealership they immediately told me that it was a bad knock sensor or something along those lines. I had my truck there for something else and the second i opened my hood and turned the truck on he said that the knock sensor was bad. He was right too becuase i had gone to an AutoZone a few days before and had a diagnostic test done and one of the codes that came up was for the knock sensor.

The mechanic told me that it wasn't anything that i needed to change out right away unless i wanted to pay a load of money. So i choose to wait on it for now.

But the noise that i have is a knocking noise that is just constantly there and increases with speed, just as you have desribed. So i would ask around about that and maybe see if that is the problem.

Posted: Oct 07 2007 at 3:36pm | IP Logged

2004 desert runner v6 a4 4x2, same on mine as well, dlr has given me all kinds of excuses.

i however beleive its a rod knock/bearing..   on cold starts 1-3 times a week i get loud knocking from a no-oil in the motor style condition that stays for a few seconds then starts to quiet down.  this used to happen every time i started it after it sat overnight for about 9 hours

with nearly 56k on the motor now and its been doing it since shortly after i purchased it..   motor runs rough, misfires at lower rpm(less than 2000 rpm usually), and gets horrable city mph.

tried switching from dealer/gtx to mobil 1 extended (15k) and changing at 5k mi.  no noticable change

p.s. anyone know where i can get the nissan full service manual for my truck