DAYTONA-ZED

When parked, at idle and the transmission in neutral there is a bumping noise that sounds like its coming from the back of the car. Could this be the fuel pump????

FairladyZ

This may sound funny but is your radio off when your car is at idle or just barely on when you are listening for the sound?

DAYTONA-ZED

Yes the radio is turned off. It sounds like a thumping sound from the lower rear of the car. Thats why i thought it might be the fuel pump. At one point i thought it was someone closing a car door behind me ,but it happened 2 or 3 times over a 15 minute period and there was no one parked behind me.

maxwell72764

Did you remember to bury all the dead bodies or maybe you left one rolling around in the trunk.

Daking350z

Could be the infamous exhaust "POP" that Nissan said didnt exist.

HCJOE

I noticed the "same" sound a week ago.....first thought it was coming from the engine compartment, raised the hood and couldn't pin point the noise at that location, walked towards the rear and the noise seemed to diminish mid way. Concluded it may be an exhaust leak or exhaust problem and haven't thought about it till I read the post today.

Not familiar with the infamous Nissan exhaust "Pop"......do know the noise I'm hearing is not coming from the exhausts pipes at the chrome tips.

Daking350z

is it like this...
Engine running..
Brrrr brrrrr brrrr brrrrr pop
brrrrrr brrrrrr bbrrr pop..

Kind of like a misfire at idle?

DAYTONA-ZED

It maybe some type of misfire and sounds similar to what you describe. Its a muffled sound like someone thumping the bottom of the rear floorpan. sounds like its coming from a little past mid-car back to the muffler area. Not saying its the muffler though. Ive also noticed the engine idles rough with the AC off ,but not sure if it is related to what im hearing. Well just another thing to have them look at when i take it to the service dept next wensday.

supsup

i have a g35 coupe ...
i have that kind of noise too!
i think the sound comes from the muffler!

Daking350z

Its a lean idle condition...Dont let nissan tell you its normal.Demand you get the NEWEST ECU software as well as the coil packs checked..I had it for many miles then swapped out my ECU and gone..Also had bad coils on my car caused by J&S...

DAYTONA-ZED

Great. Well from the info you've given at least ive got some ammo if they try to blow me off and tell me its the tooth fairy causing the problems. 1. bumping noise (possible exhaust prob). 2. Lean idle. Hope the list dosen't get longer between now and this wensday.

Thanks to all who posted in response. This board has been great with lots info.

DAYTONA-ZED

What is J&S????

supsup

hey..my car is a 2004
won't it come with the newest ECU & software already??

palmerwmd

I had/have the same problem.

A nissan dealer worked it pretty hard the other day installed a MAf and the problem is 50% less now.

Anyone else have any more comments and advice?
I am hopeful my soon to be addition of a grounding kit will fix whats left of my poor idel.

Fred..

DAYTONA-ZED

The thumping sound is not as bad as it was 4 months ago. Sometimes i never hear it all during idle, but the rough idle is still there. Nissan said it idled as normal. I may try cleaning the throttle body as a next step.

donricouga

iTrader: (2)

I just installed the maxground kit and noticed my idle was smoother.

Plus i gained 30 rwhp and a prettier engine bay. !!!























30 rwhp <--- I wish

Superhung

iTrader: (2)

I have the same sound too along with rough idle. Most likely the car is running lean. My idle was extremely smooth until the addition of my mods.

I'm still waiting for Technosquare to come out with the F-Spec flash for the '05 models so they can tune my A/F.

FLZ_Boy

I had the pop sound since I bought my Z and took it as normal noise.

I guess its something I'll take into the dealer later.

DAYTONA-ZED

I contacted them and unless i mis-understood them , they said there is nothing in their flash that will allow you to bump up the rpm to smooth out the idle. I will check their site again for updates.

jlvvega

iTrader: (2)

my car had that noise, the dealer change the fuel dampener and it was fix.