So I have a 03 single turbo 350z. An at first had a issue with the knock sensor an multiple miss fires.. changed the knock sensor. Still same issues changed the harness knock sensor problem gone. No the annoying part multiple misfires.. ugh did all the relearns an still when it warms up high but rough idle. Acceleration is just not there cars Bucky an just rough. But the idle is not like its running on 5 or something any idea suggestions. I'm thinking throttle body possibly? Input please an thanks guys

 

Anyone?

 

Had the same problem . Although not boosted my 03 did the same thing idle wise and still is due to me cleaning my throttle body with the battery still connected . Once I do the relearn it works but then icshut my car off and the ses light comes on and so does my crummy idle . I know the only way to fix it now is either to replace the throttle body or go to a dealer and have them perform the idle relearn with the consult 2 . Hope that helps . Also I think people haven't answered is because you haven't given enough detail about the turbo kit you have on it and a few other things . My 02 cents is explain more thoroughly about your car and what's exactly happening .

 

try the idle relearn in the fsm you dont need a consult 2 to do it. if that dosnt work then try pulling the plugs to read em. ive also had issues with vvt solenoids being clogged causing misfires, very easy to clean em too takes a couple minutes

 

To be honest for his and my sake , the idle relearn only works sometimes I must have did it 20 somthing times and my ecu won't remember it I've read if after a few tries if the relearn doesn't stay you need to either go to a dealer and have them do it or completely replace the throttle body . Once I do the whole relearn the car idles and responses flawlessly with no Rev hang or anything . Once the car is turned off and started back up it's back to a terrible idle and the light eventually comes back with in a few hours .


Op I hope this is your proble. I don't want you to think I'm thread jacking

 

Thanks guys the light isn't always on comes on once in a while but usually off for weeks at a time then it comes back. Miss gets worse as the car gets warmer. Plugs are showing running rich. One thing I was thinking about was when replacing the knock sensor I reused gaskets. I checked for leaks by spraying an none except its hard to get to the lower intake completely? Issue maybe?

 

So I got this rattling noise today an it sounds like vvt but would that cause a big power lose? How hard is it to clean ? Thanks again!!

 

Look through the injector harness and coil harness connectors and make sure all the wires are fully pushed into the connectors. Sometimes they can get loose and back out causing a poor connection.

Also, to do the relearn you have to meet all the requirements in the manual. Can't have 1 thing missed or it won't hold. It's a huge list of things like no check engine light, car warmed up, steering wheel pointing straight, car on a level surface, etc.

It sounds like something else is going on. What all did you change on the car before this started? If the tune sucks then it can either be rich or lean misfire.

 

Changed nothing car was tuned last year vtr. Got two codes one day an.the car fell.on its face . Knock.sensor low input an multiple random misfires. Ks code gone. Misfires stillthere. vvt solenoid is now what I'm leaning towards it has a rattle an such now. I'm pull um an clean um. An see if that helps. If I.unplug one while cars running what would it hurt? An best way to clean them? Thanks

 

You can test them that way to see if unplugging one causes no change then it's the culprit. Could be a bad condition or another sensor failing. I've heard of a few people having bad grounds in the wiring harness which throws all kinds of problems into the mix.

 

Unplugged both an no change? Chances of them both being bad?

 

unplugged what? the IVT solenoids? there is no cam timing at idle, so unless you did a WOT pull, you wont notice anything.

timing chain rattle at start up is very common with these cars. If you did have a VVT issue, a code would pop up right away.

You need to put in new plugs, tighten the gap down to 0.035"

Without new plugs, you will be chasing your tail tryin to figure out misfires.

 

It rattles every time I let off the gas? An should these throttle bodys have any play side to side

 

what does it matter what happens when you let off the gas. The important thing is when happens when you give throttle and get into boost.

I still think it's an electrical issue. You need to go through all the grounds and make sure you don't have any wires loose on the coils or injectors. Go through each connector and make sure the wires and secure inside the connector.

 

The rattle is the strange part any idea what it could be?

 

could be anything from clutch rattle, cam chain, etc. It's hard to tell without being with the car.

 

Good point .. idk would a video help? An cleaning my tb inside the housing it thumps when turning that normal

 

If you have unplugged your throttle body or moved the blades you need to do a full reset. I've never had one make a noise before.

Look up the manual procedure to do a throttle body reset. Make sure you look in the manual because a lot of things have to be correct for it to actually reset like wheels forward, no engine lights, engine at operating temp, etc.

 

Idle is smoother now still multiple random misfires idleing at 1200

 

You're going to need to provide some detailed logs or something for us to go on. Impossible to tell without it through the internet.