Engine Detonation

[big block]

I had a 2003 max that had "spark knock" so bad I had to play the radio loud. nissan replaced all 6 coil packs, i replaced the plugs, had the computer re-programmed or updated by nissan and none of these things fixed the problem. They insisted that it was not the knock sensor as it would most definetely set a check engine light and a code (which neither ever happened) I always ran premium fuel from day one. seems like the problem started after 75,000 miles. I gave up and traded the car in last december. now my wife's 2003 max with 68,000 miles is starting to do the same thing. knocks very bad around 2000 rpm especially after trans has shifted into 2nd or especially 3rd while driving around town. this problem NEVER occurs under load or under hard acceleration-which is when you would expect spark knock or detonation. knowing all of the things i replaced on the other 2003 max that fixed nothing-i am not sure what to do with this car-and i am not in a position to get rid of this car for at least 2 years!! Help-i hope someone out there has figured out that there is something wrong with this motor/sensors/computer/something!! the dealer is clueless on this one-deer in the headlights look is all i get.

[Trav1s]

Have you considered upper intake carbon build-up?

Try running a partial can of "Seafoam" through the top end by using the brake vacuum hose to draw it out of the can. I have read numerous cases on this on the VQ35DE in the 02/03 Maxima/I35.

Good luck!

[NutriaforBreakfast]

Ask the dealer to check the timing

Supposedly you can't change the timing but they cant CHECK it

[NutriaforBreakfast]

Oops bad typing. The dealer CAN check the timingbut I have heard you cant change it.

[maximaman]

thats funny my 96 knocks in idle too but not when i accelerate. i thought it was the packs but i switched out the plugs with platinum 2s and tested the packs and nothing was wrong. my knock sensor shows trouble codes once in a while but maybe that has something to do with the chip i put in it. a mechanic friend of mine said the slight knock is the... uh... the injectors and its normal for that car. what do you think?

[NutriaforBreakfast]

I doubt its the injectors. You almost have to have a stethoscopeto hear which of them is firing individually