Random Misfire. P0300

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Jul 18, 2011 | 08:37 AM

#21

Wagoner 726

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From: Charleston, SC

Ended up being a coil pack. Thanks to everyone that helped me out.

Nov 25, 2011 | 05:33 PM

#22

GWord256

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From: Cleburne, TX

Quote:

Originally Posted by Lawn Dart

It's a bad fuel injector. It should be closing before the valve but it can't and the fuel it sprays bounces off the closed valve and blows up into the plenum and gets sucked in by the other cylinders. The engine senses the overly rich condition and thinks it's misfiring and throws a PO300. Pull all your spark plugs and inspect them one by one. Whichever is carbon fouled, that's your stuck injector, change it.

Is there an easy way to test the injectors once they are pulled from the car? My whole driver side bank plugs have carbon buildup on them. Injectors aren't cheep.

Dec 2, 2011 | 06:02 PM

#23

Lawn Dart

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From: New Castle, DE

http://www.rceng.com/Fuel-Injector-Cleaning-P43C0.aspx

Aug 15, 2016 | 10:35 AM

#24

b_g777

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From: maryland

I have had a random misfire code for quite a while now> p0300. I have recently done all of the following.

-New coil packs
-New spark plugs
-Replaced all 6 injectors
-Valve Cover gasket
-RTV the plug well seals to stop the oil from getting into cylinder
-Even did a new PCV just in case there was bad pressure.

Any other suggestions on what could be causing the problem? My car has full throttle up until about 4k RPM then falls on its face and literally does have any *** passed that> And running extremely rich.

2004 350z

May 7, 2021 | 01:43 PM

#25

Lexx1221

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From: Parkesburg

Quote:

Originally Posted by b_g777

ever find out? Lolol needs to knowww

May 7, 2021 | 07:07 PM

#26

MicVelo

350Z/370Z Tech Moderator
MY350Z.COM

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From: Northern California

This is the sixth time this week. People, check the dates of the posts you’re tempted to ask questions about. This post was the last time (likely their first and only time) they posted here.

Net net, don’t expect an answer.

May 7, 2021 | 07:10 PM

#27

Lexx1221

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From: Parkesburg

Quote:

Originally Posted by MicVelo

I checked the date, taking a random stab. Don’t see the harm done bucko

May 7, 2021 | 07:14 PM

#28

MicVelo

350Z/370Z Tech Moderator
MY350Z.COM

Joined: Oct 2014

Posts: 10,315

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From: Northern California

Quote:

Originally Posted by Lexx1221

I checked the date, taking a random stab. Don’t see the harm done bucko

No harm, just trying to save you from being disappointed not getting an answer back.

May 20, 2021 | 06:21 PM

#29

GWord256

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From: Cleburne, TX

Quote:

Originally Posted by Lexx1221

ever find out? Lolol needs to knowww

Damn, make me remember my password.

I had to get my CAT replaced. Dealer said it was destroyed. Likely from something that made the engine run rich or just dump a lot of unburnt fuel.

May 12, 2022 | 12:00 PM

#30

austintillison

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Joined: May 2022

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From: AL

Quote:

Originally Posted by b_g777

bump. any other ideas?
i've been trying to fix the same exact issue on my friend's car

i've done:
6 new injectors
intake manifold gasket set
new MAF
knock sensor
knock sensor harness
crank sensor
6 new spark plugs