Nickroth09

So I bought an 04 350z with quite a few issues but paid a good price so I was well aware what I was getting myself into. So far I've replaced the left front wheel bearing, air filter, oil change, camshaft position sensor, all spark plugs, coil pack on cyl 4, cleaned out the intake and lower plenum. Issues that still remain... SRS Airbag light is flashing, misfire on cylinder 4 still.. Windows don't roll down..

So I'll back track. Originally the CEL was on for 3 codes.
P0011 - camshalft position sensor
P0300 - random/multiple misfire
P0304 - misfire on cylinder 4

So after replacing the camshalft position sensor I was left with just the P0304 code. After that I did all spark plugs, then the coil pack, now I'm waiting on a fuel injector. So far I've seen slight improvement but no real result. The code was constantly flashing, definitely not pushing out the hp it should be. And it has a distinct sound to it. It just sounds like it's running on 5 cylinders. As of now, the code remains solid, it doesn't shake as much as before (it was a pretty obvious and violent shake) now it's just a suddle vibration.

So once I do the fuel injector, I'll update the post but I'm not very hopeful right now because it just seems like a bigger issue that just a misfire. I've read other posts on misfires but no one seems to have a similar, more CONSTANT issue. Like I crank it up and it's constantly running weird not just at low rpms or high rpms.

My next step if FI don't work, compression test and a test of the ecu. After that... I have absolutely no idea. Any advise or recommendations would be gladly accepted. Thank you

icer5160

iTrader: (4)

Before you went the coil pack route, try doing a "power balance test" this is something you should check even before you get the new fuel injector.

Basically leave the engine running/idling and pull the injector power plugs one at a time. If all the injectors are working properly, you should see a noticeable change in the engine's idle/rpm. Plug each injector back in before moving onto the next one. If you get to an injector that shows no change in the idle/rpm when unplugged, then you found your problem! Usually a bad injector, but could also be a loose connection or fault in the wiring harness.

Getting to each injector on the VQ35DE is not the easiest task because of the intake plenum. Some items may need to be moved out of the way for easier access. The main obstacle is the throttle-body intake piping. Followed by a few wiring harness bolts/brackets. If my memory serves, cylinder number 4 is the middle cylinder on the driver's side of the engine block.
Good Luck! I hope the new injector solves your issue. One more side note, if you have one injector failing and it's a high mileage car, it's recommended to replace them all. There's a good chance the other 5 could start failing shortly after.
-Icer

icer5160

iTrader: (4)

Also, you mentioned you replaced all the spark plugs. Which model/brand did you use? I hope these were the NGKs. I have an 06 (Revup VQ35DE), the OEM plug P/N from NGK is PLFR5A-11. This type of plug has a crush washer on it. For proper installation of the new plug, hand thread it in with your extension/socket until you feel it bottom out, then give it another 1/4 to 1/2 a turn with your wrench attached and stop.
Good Luck again!
-Icer

Nickroth09

Now if I'm understanding you correctly, you suggest I start the car and pull the coil packs out one at a time to test them to see if it makes a difference? Or Like a wiring harness connecting to the injectors? Cause if you're talking about wire connecting to the injectors, I wouldn't exactly know where to find those while everything is still together.

icer5160

iTrader: (4)

Hi Nick,

That's a negative, pulling the coil packs will only kill the spark and since you've already replaced the coil pack for cylinder #4 you've ruled this out for the most part. There's still a chance that there's a wiring harness fault for this coil pack. You can pull the coil pack and ground it to test for a good spark. It's rare, but wiring harness faults or issues with the PCM can cause these types of issues.

I'm talking about pulling the wiring harness connections to your fuel injectors only. The injectors and wiring harness plugs that feed them are near the coil packs/valve covers, but tucked further under the lower intake plenum. Just google VQ35DE Fuel Rails and you should find some good pictures of where the plugs and injectors are.
Good Luck!
-Icer

Nickroth09

Okay I will give that a shot thank you

icer5160

iTrader: (4)

Hi Nick,

I was just thinking, it's going to be very difficult to get to those injector plugs while the intake plenum is still installed on the engine block. A good shop with a high level scan tool should be able to achieve the exact same test using their scan tool. Instead of manually disconnecting the injectors, the scan tool will work through the Z's PCM to electronically shut off each injector one at a time. If you know of a good shop near you that is willing to do this very quick and simple test for free, go that route first!
-Icer

Nickroth09

Ahhhh that is an excellent idea!

jv350z

iTrader: (6)

^ Not sure, but throwing it out there.. Perhaps this is the same test available through UpRev/Cypher - "Cylinder Power Test"

Jewelianc

I'm not 100% sure if you guys may have answered my issue already in this post, but I'm not 100% sure though like I said. I've ready everything you all have said and it sounds like I'm heading in the right direction, but to make sure, I'll start by telling you what I have. 2005 350Z Base Model Manual Transmission. I bought the car about 3 weeks ago from some one down here in West Palm Beach, FL. The first few main things I did to the car was the normal oil & filter change, spark plugs and a new fuel pump because the car wasn't getting enough gas to pass 2500rpm. After that, still when I would come to red lights, my car would turn off. I went ahead and bought a new throttle body. The car was running stronger, but would still turn off. At least once in the morning on my way to work or class and in the afternoon it would turn off every other light. It won't turn off while I'm driving, but I'm also not punching it or driving it like I would because I know the car is sick. I just changed the Mass Airflow sensor yesterday and still the same issue. The idle can be held a bit longer, but still turned off on me 4 times before I could get home. At one point it was trying to turn off in 1st gear, so I had to give it more gas to keep it alive and pump the pedal while it struggled to stay on after just turning it on from a quick stop at CVS. I've already been to AutoZone and Napa to plug their code reader into my car, but it won't read the computer even though it lights up. Also, the check engine light doesn't come even when I first turn on the car. Someone please help me before I spend more money into the car

Jewelianc

The car also has a custom exhaust. Single, as apposed to Dual

travlee

iTrader: (8)

my money is on camshaft position sensors

Jewelianc

I changed both camshaft position sensors and crankshaft position sensor

travlee

iTrader: (8)

at this point, instead of throwing parts at it..... take it to nissan for a proper diagnosis. we can guess all day long, but without putting our hands on it we wont know

Jewelianc

Thank you. At this point, that is my best direction to head. I just didn't want to have to spend money to take it to the dealer for a diagnosis, but I guess it's my only option if I don't want to have to put out even more money that I would have to

eZg

iTrader: (5)

Can't you find a decent independent shop?? Dealers suck....at least in my experiences.

rearranged

It's gotta be cheaper to take it to Nissan or a reputable mechanic than to just keep replacing parts without knowing what's really going on.