The_Assassin

Hey guys, my idle is fluctuating between 1500 and 2 k rpm. I read thru a couple of the threads on here and still can't seem to figure it out. At first my mechanic said his scanner was showing the throttle body code so I ordered 2 used and he changed those out, code went and and yet the problem remained. Not sure what else to do, I am thinking maybe somehow my tune went bad? I left the car and went on vacation during the cold season then when I came back i noticed this issue. It actually started a bit of rough idle before the trip but not this bad. Mechanic tried the relearn using his scan tool and also tried to do it manually. Any suggestions? car is a 2007 tuned 350z hr with oversized intakes and big injectors

UPDATE

Just providing you all with an update. I am still having this issue, I have had the car checked out by multiple mechanics. All have no idea what is going on. I actually went to a Nissan dealership and had them do a diagnostic test on the car and they have no idea what is the exact problem. They suggested that I buy brand new throttle bodies from them totally $2200. They are not even sure this will correct the issue. However they did say they saw a misfire code in their scanner from a few cycles ago.

Today I took the car to a popular shop in the Miami area. He tried and failed saying he doesn't believe its a mechanical issue. I am thinking maybe my an injector went bad casing the fluctuating idle and the miss fire found in the history. I am thinking of going to my tuner to see if he can possible use uprev to control the idle. That is my last hope I have no idea what else to do. If this fails I might sell the car and get a daily to drive around before picking up a new toy in a few months. Any suggestions?

jhc

Grab a vacuum guage, hook it onto intake plenum. I'll buy you a pint if it's not a vacuum leak. Post up when you find the problem!

The_Assassin

Thanks for the response, he actually did check for vacuum leaks but I didn't see him use a special gauge or anything. You think its best to try this and not take it to the tuner? I already wasted money on throttle bodies that I am not even sure was the issue. Hopefully I can resell If I find out they are in working condition.

jhc

It does sound like you have a lot of moving parts. With an inexpensive gauge, this is an easy point to rule in/out. gl

92K1500

iTrader: (1)

My running/idle issue was from the hose that hooks to the bottom of the intake tube after the MAF being split. But that was on a DE car and I don't know if the HR cars have that.

travlee

iTrader: (8)

with car running, spray brake cleaner around all the connections for the intakes, if you have a vacuum leak, you will know

zakmartin

A smoke test will reveal pretty much any leak. Most halfway decent shops have an automotive smoke machine.

The_Assassin

Yea I believe thats how my mechanic checked. He said he didn't find any leaks.

The_Assassin

I will take another look at it on saturday. If I don't find anything I will take it to another mechanic.

Anyone think that there could be a problem with my tune ?

zakmartin

Without seeing what the shop actually did during your tune, it's anyone's guess. That being said, if the problem surfaced right after they performed it, then odds are it'd be a good place to start.

iideadeyeii

iTrader: (6)

Is this boosted? Otherwise, why larger injectors?

The_Assassin

No the problem started maybe 6 months or so after the tune. He did have a problem with injector scaling though. With the bigger intakes and injectors the car was idling horribly until he got it sorted out.


I had big plans for the car was eventually going to get a Boosted performance kit. I have dual 3.5 inch custom made intakes and some people on here also changed their injectors when they got theirs installed so I figured why not do it.

The_Assassin

Just providing you all with an update. I am still having this issue, I have had the car checked out by multiple mechanics. All have no idea what is going on. I actually went to a Nissan dealership and had them do a diagnostic test on the car and they have no idea what is the exact problem. They suggested that I buy brand new throttle bodies from them totally $2200. They are not even sure this will correct the issue. However they did say they saw a misfire code in their scanner from a few cycles ago.

Today I took the car to a popular shop in the Miami area. He tried and failed saying he doesn't believe its a mechanical issue. I am thinking maybe my an injector went bad casing the fluctuating idle and the miss fire found in the history. I am thinking of going to my tuner to see if he can possible use uprev to control the idle. That is my last hope I have no idea what else to do. If this fails I might sell the car and get a daily to drive around before picking up a new toy in a few months. Any suggestions?

iideadeyeii

iTrader: (6)

Put the stock injectors back in. I already questioned why you had larger injectors and you failed to provide a reason to actually have larger injectors.

The_Assassin

I had already answered your question in my previous post.

iideadeyeii

iTrader: (6)

Adding custom intakes and a larger exhaust does not justify installing larger injectors.

So no, you did not provide a LOGICAL reason to installing larger injectors.

dboyzalter

iTrader: (3)

Put back to stock and run stock tune and see what happens...

You can get new throttle bodies from Z1 for like $750 if you think thats your issue but I wouldn't bother.

The_Assassin

Dude I guess you missed the part where I was planning to get a boosted performance kit from sasha. He took long to get back to me and I changed my mind. I got the injectors at a good price so why not if I was planning to go turbo.

Thanks for the heads up on the throttle bodies. Yea I have an appointment with my tuner for next Saturday.

The_Assassin

Just to provide some sort of closure to this issue. I was never able to fix my Z. I got rid of it a few months ago and picked up a c7 corvette 3LT Z51 performance. Will be posting that up in the other cars section soon.

iideadeyeii

iTrader: (6)

All you had to do was re-install the stock injectors. Told you like 3 times smh. . .