Random Misfire Code..

Munts · 07-31-2016, 09:25 PM

Hi all,

Been dealing with an annoying problem for the past couple of weeks.

My 2009 Z has been throwing the P0300 code off and on. My buddy works at a Toyota dealership and I brought it in for him to take a look. He said everything looks good, and I can't know what is wrong until I find out what specific cylinder is misfiring?

I have cleared the code a couple of times.. I notice that when I cold start it, and drive for about 20 seconds it will come on every once in a while.

The car starts up, pulls, idles, and drives fine. Can anyone give me some advice, or have any thoughts on what could be wrong?

Thank you!

Jayhovah · 07-31-2016, 09:29 PM

I had one in my road trip home after installing a turbo kit... Tuner told me to install GTR plugs but I didn't get around to it for about 6 months!!!! Code never resurfaced though. I guess the circumstances were pretty different for me.. but I wasn't boosting when it happened just stopped for gas, then started up and got back on the road and it threw the code so maybe yours was random and won't resurface either?

SouthArk370Z · 08-01-2016, 09:21 AM

https://duckduckgo.com/?q=P0300+site%3Athe370z.com

Gixxerman · 09-05-2016, 08:34 PM

I am currently having the same issue. Did you ever figure out what it was?

Smashley · 09-07-2016, 03:37 PM

Same issue here after a cold start during fall\winter months.

Dreadnaught · 09-07-2016, 07:14 PM

Just so I can try to help you out Munts, you're saying the misifre only happens when it's on a cold start primarily? And when it runs for a couple of minutes it goes away?

Gixxerman · 10-02-2016, 09:54 PM

It doesn't go away for me.

Dreadnaught · 10-03-2016, 07:33 PM

I saw a tech when I was at Mercedes work on a 220 chassis that had this similar issue. It turned out to be the solenoid in the fuel injector getting stuck when it was cold out. Once they vehicle ran for a minute the misfire went away.

The Tech who had this car took a heat gun to the fuel injector and hooked up a DMM to the injector. Once the injector started to get warm/hot, the voltage/resistance would change.

The tech replaced the injector and all was well.

Jhill · 10-03-2016, 08:00 PM

Can you get access to data and see what cylinder is misfiring? if not you will need to do a cylinder balance test to isolate what cylinder is misfiring. If all the. Need to start thinking about things they all share, fuel pressure/flow, ignition voltage, maf readings, crank sensor, etc. So first step is it one or all.

Dreadnaught · 10-09-2016, 10:28 PM

Also, the misfire is only when you start it up after sitting for a while, you could have a cracked head. You could pressure test the cooling system.

07-31-2016, 09:25 PM	#1 (permalink)
Munts Base Member Join Date: May 2014 Location: St Paul, Minnesota Posts: 101 Drives: 2009 MT Touring Rep Power: 10	Random Misfire Code.. Hi all, Been dealing with an annoying problem for the past couple of weeks. My 2009 Z has been throwing the P0300 code off and on. My buddy works at a Toyota dealership and I brought it in for him to take a look. He said everything looks good, and I can't know what is wrong until I find out what specific cylinder is misfiring? I have cleared the code a couple of times.. I notice that when I cold start it, and drive for about 20 seconds it will come on every once in a while. The car starts up, pulls, idles, and drives fine. Can anyone give me some advice, or have any thoughts on what could be wrong? Thank you!

08-01-2016, 09:21 AM	#3 (permalink)
SouthArk370Z Premium Member Join Date: Nov 2010 Location: South Arkansas Posts: 8,435 Drives: 2014 Challenger Rep Power: 324197	https://duckduckgo.com/?q=P0300+site%3Athe370z.com __________________ Steering Lock Links - Search The370Z Bookmarklet - FSM @ NICOclub Mankind has progressed past the need for war but we haven't evolved that far. - NachoMahma

09-07-2016, 07:14 PM	#6 (permalink)
Dreadnaught Track Member Join Date: Dec 2009 Location: Farmington, Utah Posts: 582 Drives: 14 SR 370z 6MT Rep Power: 10139	Just so I can try to help you out Munts, you're saying the misifre only happens when it's on a cold start primarily? And when it runs for a couple of minutes it goes away? __________________ Ford Diesel and Heavy Line Technician at your service.

10-03-2016, 07:33 PM	#8 (permalink)
Dreadnaught Track Member Join Date: Dec 2009 Location: Farmington, Utah Posts: 582 Drives: 14 SR 370z 6MT Rep Power: 10139	I saw a tech when I was at Mercedes work on a 220 chassis that had this similar issue. It turned out to be the solenoid in the fuel injector getting stuck when it was cold out. Once they vehicle ran for a minute the misfire went away. The Tech who had this car took a heat gun to the fuel injector and hooked up a DMM to the injector. Once the injector started to get warm/hot, the voltage/resistance would change. The tech replaced the injector and all was well. __________________ Ford Diesel and Heavy Line Technician at your service. Last edited by Dreadnaught; 10-03-2016 at 07:37 PM.

10-09-2016, 10:28 PM	#10 (permalink)
Dreadnaught Track Member Join Date: Dec 2009 Location: Farmington, Utah Posts: 582 Drives: 14 SR 370z 6MT Rep Power: 10139	Also, the misfire is only when you start it up after sitting for a while, you could have a cracked head. You could pressure test the cooling system. __________________ Ford Diesel and Heavy Line Technician at your service.

09-05-2016, 08:34 PM	#4 (permalink)
Gixxerman Base Member Join Date: Jan 2016 Location: Delaware Posts: 24 Drives: 2009 370Z Grey Rep Power: 9	I am currently having the same issue. Did you ever figure out what it was?

09-07-2016, 03:37 PM	#5 (permalink)
Smashley Enthusiast Member Join Date: Aug 2013 Location: Maryland Posts: 347 Drives: mt/sport/tour MB Rep Power: 11	Same issue here after a cold start during fall\winter months.

10-02-2016, 09:54 PM	#7 (permalink)
Gixxerman Base Member Join Date: Jan 2016 Location: Delaware Posts: 24 Drives: 2009 370Z Grey Rep Power: 9	It doesn't go away for me.

10-03-2016, 08:00 PM	#9 (permalink)
Jhill Track Member Join Date: Mar 2016 Location: San jose Posts: 846 Drives: 2013 370z sport Rep Power: 3384	Can you get access to data and see what cylinder is misfiring? if not you will need to do a cylinder balance test to isolate what cylinder is misfiring. If all the. Need to start thinking about things they all share, fuel pressure/flow, ignition voltage, maf readings, crank sensor, etc. So first step is it one or all.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Random Cylinder Misfire with CAI/Short Ram Intake	foodgoesNryan	Intake/Exhaust	4	12-10-2014 12:05 PM
Misfire code after install g3 intake	370zbob	Intake/Exhaust	6	01-17-2013 04:52 PM
Stillen G3's and code P0300 Random Misfire?	The Shocker	Intake/Exhaust	11	11-21-2012 09:25 PM
P0300 random misfire code HELP!	Alchemy	Nissan 370Z Warranty / Scheduled Maintenance / Servicing / Repairs	12	12-02-2011 05:34 PM