when i start my car on a cold start right after the engine revs up it makes a loud "EEEEHHHHHHHHHHHHHHHHH" sound and shoots down the RPM quick, like more than usual, its not high pitched, and sounds real mechanical, i've read the instructions about greasing up the starter, but i'm not sure that is the problem because the sound described is completely different. the sound goes away whenever the engine is warmed up and i start it, and it doesnt always make the sound on a cold start, but it does it pretty often. can anyone help me? also, i dont know what this is either, but when i make a U-turn i feel this vibration, i dont think its a balancing problem with my wheels becuase i got them balanced and its still there

 

alternator!

 

sounds like your belts, maybe a belt tensioner?

 

Since it only makes the sound when starting, I think that's your clue. Try regreasing the starter and then see if it goes away. Even if it's not that, you'll be out like 4 bucks for the grease and the procedure takes less than an hour.

 

Yes, regrease your starter. Go to the 4th gen how-to's;link in my sig. and go down to engine and you will see it.

 

If it sounds like metal grinding (not that loud but noticeable), then your starter has to be regreased, as said above. I have the same problem just never gotten around to doing it, I should do it before my starter goes bad. www.motorvate.ca has an awesome write up

 

what about the vibration?

 

Check to see if your CV boots are ripped.

http://www.motorvate.ca/mvp.php/400

 

CVs don't have anything to do with start ups buddy, but it is your starter. Same thing with my car the starter binds when I start it. I'm just to lazy to fix it, and when it breaks I will have it fixed since my car is under warranty.

 

Yes, I know that. He said when he makes U-Turns he feels vibrations and when both my cv joints were bad it did the same thing. You should read EVERYTHING before posting.

 

my bad as I said "I'm lazy"!!!

 

If the noise continues after the car is started, my vote is for either worn alternator bearing or a bad idler adjustment pulley and/or tensioner. Your car may fall under the alternator recall - contact your Nissan dealer with your VIN# handy to see if you qualify.

To isolate the sound, get a 3' length of ordinary vacuum hose & use it as a mechanic's stethescope (one end in your ear, one end near the suspected sources of the noise) in the engine bay while a helper starts your car. This will allow you to get a better sense of exactly where the noise is coming from.