G35_S13_Coupe

Ok here is the rundown... I have been trying to figure out this issue for a couple months now and am at my breaking point.

Motor is an s14 blacktop that is all stock except for fmic kit.

The car seems to idle fine, but has a slight misfire. My wideband is pegged at 10.0. Vacuum reads at 15-17.

Things I have checked and replaced:

New o2 sensors
MAF
Checked all vacuum lines for leaks
Checked intercooler couplers for tightness/leaks
Good compression 150psi on all 4
Swapped out coil packs
Checked timing
New spark plugs
Adjusted IACV
Adjusted TPS

I'm trying to think of what else I may have checked, but I think that is most of it. Again, I have tried researching as much as I can, but none of other suggestions/ problems have resolved my issue.

Thanks

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4x4le

Have you checked fuel pressure?
Is your bov opening?
You would need consult to know if your o2 sensor id's actually working, but have you checked?

801nismo104

recheck your maf sensor and the wiring

Frank_Jaeger

Did you gap your spark plugs? Are they the right temperature?

Did you check to see if you're getting spark / fuel on each cylinder?

4x4le

If he wasn't getting spark on a cyl he would be getting a false lean and if he was getting no fuel he would also be getting a false lean.

The plugs could lead to improper combustion however it would be hard to get a false rich of 10:1

G35_S13_Coupe

Haven't checked fuel pressure yet.

I have gapped the plugs at 44, 33, and 28 thousandths and didn't help.
Plugs are Ngk bkr6e's

I actually unloomed the maf wiring already to check it and tried a couple different mafs that I know are good (came off a good running car)

I'm getting spark on all cylinders and obviously plenty of fuel

Changed out the fuel filter already (z32)

Finally I know the o2 sensors are good as I bought brand new ones from Enjuku. They made a slight difference, but didn't solve my problem.

Bov is opening just fine and I have even swapped it out with a different one.

I even tried a different waste gate actuator.

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hobbs

Did this issue start to happen or did you purchase the car with this issue?

I would check the MAF voltages with either consult or a multimeter, while the MAF may be good you can still have a bad ground, which would give you a false airflow reading causing fueling issues.

fliprayzin240sx

Have you checked your base line timing? Make sure its good to go and leave your plug gap to .030. Do you have an aftermarket fuel pressure regulator? Make sure you're getting the correct pressure for fuel. Then the other things would be ECU water temp sensor and maybe a bad ECU all together.

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rwtf

check cts?

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G35_S13_Coupe

I bought the car with the issue thinking it was a simple boost leak. MAF voltage has also been checked.

Ive checked the base timing what feels like 100 times. My plug gap is at .030 now. I am running the stock fpr, but I have an adjustable one with a gauge I may throw on to see what my pressure is at. I just put the coolant temp sensor on my list of things to check. I also have thought maybe the ecu is bad...? Any way to tell? I pulled the cover off and everything looked ok, no corrosion or loose pieces.

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inopsey

when you check the timing do you disconnect the tps? it makes a difference.

ultimateirving

Can you tell us what rpm it is idling at?
Also have you considered the injectors? Checked them to make sure none are stuck open or operating incorrectly. Also verify injector o rings are not leaky or allow fuel through.

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Z32 with lq4 swap
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