P0300 and P0302, HELP!

jameeljoker · 01-04-2016, 09:27 PM

Hey guys, let me start off by saying that I have searched the forum for these codes and read each page of each article. With that being said, I changed out my coilpack and plug, and even tightened the pins in the connector on the coilpack yet the car still has a misfire in cyl 2. I have no idea what else could be causing this. Mods are stillen gen 3 with dry filters, berk HFC and HKS HI-Power exhaust. Anyone has any input on this issue that can help? I'm wondering if to take it to the dealer but my car is slammed and i'm not sure if they'll turn me away due to the mods.....
Any help is greatly appreciated
Thanks

jameeljoker · 01-04-2016, 09:49 PM

Also cleaned out the MAFs with a MAF cleaner and didn't touch the hot wires, misfire still there....

SouthArk370Z · 01-04-2016, 11:24 PM

Check the coil/plug connection.

MAF problems will (usually) affect the whole bank, not just one cylinder.

Dealer could possibly refuse warranty on your suspension but not other items that haven't been modified.

jameeljoker · 01-04-2016, 11:29 PM

Quote:

Originally Posted by SouthArk370Z

Check the coil/plug connection.

MAF problems will (usually) affect the whole bank, not just one cylinder.

Dealer could possibly refuse warranty on your suspension but not other items that haven't been modified.

Thanks man, already checked the connection several times, didn't help. Spark plug I removed smelled heavy of fuel though. Would that mean I have to change the other plugs and coilpacks on the same bank?

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SouthArk370Z · 01-04-2016, 11:37 PM

Quote:

Originally Posted by jameeljoker

... Spark plug I removed smelled heavy of fuel though.

That sounds like the plug is still not firing. Check the primary side with a VOM (may take a sensitive meter to see the quick pulses) and make sure the coil is being pulsed. FWIW, the plug fires when the coil is de-energized.
Not sure how you can check the secondary side. Back in The Good Ole Days, we just laid the spark plug on the block and looked for a spark.

Quote:

Originally Posted by jameeljoker

Would that mean I have to change the other plugs and coilpacks on the same bank?

It sounds like it is only the one cylinder messing up, so the rest of the bank is probably OK.

You may have a fuel injector problem.

nismolucino · 01-06-2016, 11:24 AM

I would probably lean towards a stuck injector, thats assuming your definitely getting spark.

jameeljoker · 01-08-2016, 07:15 PM

Thanks a lot guys, going to check it out this weekend and see whats going on. In the event its not the injector, anything else that may lead to this issue? Has anyone pulled off the manifold and changed the injectord themselves? Wasn't able to find a DIY

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nismolucino · 01-08-2016, 07:36 PM

Yes I have you just pull the plenum off and then you can pull the rail it's pretty easy.

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SouthArk370Z · 01-08-2016, 09:24 PM

Quote:

Originally Posted by jameeljoker

... In the event its not the injector, anything else that may lead to this issue? ...

A wet plug is a sign of no spark or an over-active injector. I can't think of anything else that could cause your symptoms. Maybe someone else can come up with something.

jameeljoker · 01-08-2016, 09:43 PM

Quote:

Originally Posted by SouthArk370Z

A wet plug is a sign of no spark or an over-active injector. I can't think of anything else that could cause your symptoms. Maybe someone else can come up with something.

Initially the plug smelled heavy of fuel and was pretty much done. Changed that and the coilpack and symptoms still continued

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Capncorroded · 03-11-2019, 08:38 PM

What was the outcome of this? Im having the EXACT same issue, and none of the basics.

01-04-2016, 09:27 PM	#1 (permalink)
jameeljoker Base Member Join Date: Apr 2013 Location: West Palm Beach Posts: 220 Drives: 370z pearl white Rep Power: 12	P0300 and P0302, HELP! Hey guys, let me start off by saying that I have searched the forum for these codes and read each page of each article. With that being said, I changed out my coilpack and plug, and even tightened the pins in the connector on the coilpack yet the car still has a misfire in cyl 2. I have no idea what else could be causing this. Mods are stillen gen 3 with dry filters, berk HFC and HKS HI-Power exhaust. Anyone has any input on this issue that can help? I'm wondering if to take it to the dealer but my car is slammed and i'm not sure if they'll turn me away due to the mods..... Any help is greatly appreciated Thanks

01-04-2016, 11:24 PM	#3 (permalink)
SouthArk370Z Premium Member Join Date: Nov 2010 Location: South Arkansas Posts: 8,435 Drives: 2014 Challenger Rep Power: 324198	Check the coil/plug connection. MAF problems will (usually) affect the whole bank, not just one cylinder. Dealer could possibly refuse warranty on your suspension but not other items that haven't been modified. __________________ Steering Lock Links - Search The370Z Bookmarklet - FSM @ NICOclub Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

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01-04-2016, 09:49 PM	#2 (permalink)
jameeljoker Base Member Join Date: Apr 2013 Location: West Palm Beach Posts: 220 Drives: 370z pearl white Rep Power: 12	Also cleaned out the MAFs with a MAF cleaner and didn't touch the hot wires, misfire still there....

01-06-2016, 11:24 AM	#6 (permalink)
nismolucino Enthusiast Member Join Date: Mar 2013 Location: Rahway,NJ Posts: 297 Drives: 2010 40th 370z Rep Power: 364	I would probably lean towards a stuck injector, thats assuming your definitely getting spark.

01-08-2016, 07:15 PM	#7 (permalink)
jameeljoker Base Member Join Date: Apr 2013 Location: West Palm Beach Posts: 220 Drives: 370z pearl white Rep Power: 12	Thanks a lot guys, going to check it out this weekend and see whats going on. In the event its not the injector, anything else that may lead to this issue? Has anyone pulled off the manifold and changed the injectord themselves? Wasn't able to find a DIY Sent from my SAMSUNG-SM-G900A using Tapatalk

01-08-2016, 07:36 PM	#8 (permalink)
nismolucino Enthusiast Member Join Date: Mar 2013 Location: Rahway,NJ Posts: 297 Drives: 2010 40th 370z Rep Power: 364	Yes I have you just pull the plenum off and then you can pull the rail it's pretty easy. Sent from my SM-G900V using Tapatalk

03-11-2019, 08:38 PM	#11 (permalink)
Capncorroded Base Member Join Date: Mar 2018 Location: NY Posts: 11 Drives: 2016 370 Nismo Rep Power: 7	What was the outcome of this? Im having the EXACT same issue, and none of the basics.