Codes P0300 and P0301, Injector problems?

Tiny
OCTANE1Z
  • MEMBER
  • 2014 INFINITI QX60
  • 3.5L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 183,332 MILES
I'm getting code P0300 and P0301. I have replaced all plugs and cylinder 1 bank 1 coil and still have a misfire and a rich/ heavy fuel odor without any visible leaks. I have cleaned MAF and a new filter and the cylinder is making spark that I think is strong enough to ignite fuel. I plan on changing the PCV valve when I can afford it next. I was wondering if anybody had the coil and fuel injector pinout and wiring diagram as well as what to be looking for while testing with a multimeter - ohms, volts, resistance, pass/fail range for everything?
Wednesday, October 16th, 2024 AT 5:42 PM

30 Replies

Tiny
KEN L
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Was the #1-cylinder spark plug black or wet? If so, you have a stuck fuel injector. I would do a compression test on that cylinder as well. Here is how to test the fuel injector:

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Here are the engine wiring diagrams which show the fuel injectors and ignition coils, let me know what you find. Also, please go over this guide:

https://www.2carpros.com/articles/automotive-engine-misfire-code-p0300-causes-and-solutions

Check out the images (below). Please let us know what happens.
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Thursday, October 17th, 2024 AT 9:45 AM
Tiny
OCTANE1Z
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I am not sure which plug is which cylinder as my wife hired a mobile mechanic for the plugs and coil and it didn't help. The problem started immediately after we stopped and filled up her tank on a Sunday evening. I have hooked the 'bad/old coil up and the 'worst' looking plug up to bank 2 and the coil makes spark and the plug sparks still. So those weren't the issue. The PCV hose collapsed and the nipple part has oil on it as well. I'll post the plugs as she was handed by the mobile tech.
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Friday, October 18th, 2024 AT 12:01 AM
Tiny
KEN L
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The spark plugs look okay, I think we should do a compression test on cylinder #1.

Please go over this guide:

https://www.2carpros.com/articles/how-to-test-engine-compression

You can rent the gauge set at the auto parts store for free. Let me know how it goes.
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Friday, October 18th, 2024 AT 11:13 AM
Tiny
OCTANE1Z
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I will have to wait until this next weekend to just buy a compression tester, plug socket, test light and multimeter. I asked my wife to stop and have the codes checked and printed and this is today's list of 'that isn't good'. Is it possible for the misfire to cause the CVT transmission essentially freak out and jerk and slam motor mounts just while using automatic and trying to just maintain the speed limit, but when driven in tap shift or 'manual' the trans operates just fine?
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Saturday, October 19th, 2024 AT 9:03 PM
Tiny
KEN L
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Yes, when the engine is not running correctly it will make the transmission act funny. If you upload a short video of the engine cranking from under the hood I can tell if the engine is hurt or not.
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Sunday, October 20th, 2024 AT 10:49 AM
Tiny
OCTANE1Z
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I can upload that as soon as I get it put back together. I ohm tested the 1, 2, 3 cylinder injectors and they read 1-14.5
2-14.8
3-15.2
Spark plug from cylinder 1 was wet and now I'm trying to figure out wiring
and how to ohm test the old and new coils before I put it back together. White- power
Black - ground
Green- signal?
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Monday, October 21st, 2024 AT 1:19 PM
Tiny
OCTANE1Z
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Here's the plug NGK Iridium LKAR-7BIX-115 that the mobile mechanic put in and today's scan after swapping coils with #2.
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Monday, October 21st, 2024 AT 3:31 PM
Tiny
OCTANE1Z
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And a video of it starting and idling. I'm not sure what the whining sound is at the beginning? Possibly ABS system?
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Monday, October 21st, 2024 AT 4:11 PM
Tiny
KEN L
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I do not see the video?
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Tuesday, October 22nd, 2024 AT 10:22 AM
Tiny
OCTANE1Z
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Hmmm let me try again.
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Wednesday, October 23rd, 2024 AT 12:51 AM
Tiny
KEN L
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Thanks for the video, it seems like it is running okay, did you do the compression test? If so, what is the reading? Thanks for the video, it helps.
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Wednesday, October 23rd, 2024 AT 9:52 AM
Tiny
OCTANE1Z
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Here's from start-up. Do I need to re learn the TB if I unplugged it when I was doing coil swap? I'm going to buy a compression tester this weekend and do all cylinders. The misfire followed when I moved the 'new replacement coil' to cyl2 and 2 to 1cyl then had codes for 1- and 2-cylinder misfires. I took the new one out and put in the original coil from 1st cylinder into 2 due to access and the idle cleaned up a bit bit cylinder 1 is still being goofy. I'm thinking of using seafoam after the compression test this weekend or possibly before, any thoughts on this?
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Wednesday, October 23rd, 2024 AT 2:19 PM
Tiny
KEN L
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That looks like the engine is okay, but you say if the swap the coils around it follows the bad coil? I would get a replacement coil for that one and see what happens. Also, I would rescan the car for codes, this guide can help:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please go over this guide and get back to us.
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Thursday, October 24th, 2024 AT 9:18 AM
Tiny
OCTANE1Z
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Yes, it followed the coil as well as the cylinder 1 misfire is still present so there were two misfires until I took out the brand-new coil and put the original coil from one in. Then started the car and it definitely cleaned up the idle a bit, but it still runs like crap. Idle is up and down, lack of power until about 2,000 RPMs and then what sounds like a tick/tap when driving and only above 2k+ and only wants to drive when using manual shifting. When using automatic the engine shakes and slams like as if it only had 2 motor mounts with no accel or decel mounts. Also, this is the plug out of cylinder 2 and a 1/4 of fuel 60 miles with a can of sea foam in the talk.
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Friday, October 25th, 2024 AT 7:03 AM
Tiny
KEN L
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It sounds like you may have a clogged catalytic converter, I would go over this guide to see if you can confirm the issue:

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

Please go over this guide and get back to us.
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Friday, October 25th, 2024 AT 11:03 AM
Tiny
OCTANE1Z
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Here is a quick video of the sound. The high pitch rattle sound closer to the end.
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Saturday, October 26th, 2024 AT 9:19 AM
Tiny
KEN L
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The high pitch rattle can be the cat, we still need the compression test done. Thanks for the video.
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Saturday, October 26th, 2024 AT 9:42 AM
Tiny
OCTANE1Z
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I'm literally doing that right now. And on cylinder:
1 - 150 psi no oil
150 psi w/oil in the cylinder
2 - 155 psi no oil
3 - 165 psi no oil
5 - 185 psi no oil
Battery at 12.50v
Injector harness read
Cyl.1
White- 12.25v
Black- 12.25v
Green-.06 cranking max
Cyl.3
Green signal-.12 cranking
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Saturday, October 26th, 2024 AT 8:36 PM
Tiny
KEN L
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Nice work, the compression looks okay. I don't see cylinder 6 though. Is the injector on #1 getting signal? It sounds like the #1 fuel injector is bad; I would replace it but first we can run this test:

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Here is how to replace the fuel injector. Check out the images (below). Please let us know what happens.
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Sunday, October 27th, 2024 AT 11:44 AM
Tiny
OCTANE1Z
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I still need to test #4 and #6 compression. That was today's plans, but the day got away from me. I have used a stethoscope, and the injector clicks while running and I ohm tested the first 3 cylinders a they read.
I meant to say 'coil harness' read the next.

1 - 14.5
2 - 14.8
3 - 15.2

Weathers dependent, I will comp test the last 2 cylinder tomorrow and get that Info to you.
What are your thoughts on maybe the spark is weak? Does that happen a lot? I also have a new intake boot on order because hers was rotted/torn.
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Sunday, October 27th, 2024 AT 9:57 PM

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