P0300 misfire - Nissan 350Z Forum, Nissan 370Z Tech Forums
User Tag List

 
LinkBack Thread Tools Search this Thread
post #1 of 2 (permalink) Old 04-03-2017, 11:32 PM Thread Starter
Junior Member
 
Join Date: Apr 2017
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
P0300 misfire

Hello, I have a stock 03 350z I accidently double down shifted causing an over rev.
Since doing this it misfires under load, (P0300- multiple misfire) it idles and drives fine if you take it easy.
So I put new spark plugs in and checked the compression all 6 were right on 150psi.
I'm not finding any vacuum leaks, any ideas of a sensor or something that could have been affected, or I am wondering about injectors, but it doesn't seem like multiple ones would go out at once?
Thanks.
Dusty Ewing is offline  
Sponsored Links
Advertisement
 
post #2 of 2 (permalink) Old 04-04-2017, 10:01 AM
Touring Member
 
dkmura's Avatar
 
Join Date: Feb 2004
Posts: 613
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 48 Post(s)
Welcome and sorry to hear about your problem. By "double downshifting", I assume you missed TWO gears as you attempted to shift down? If it was a fifth to third misshift, and you hit first gear instead, you might have a BIG over-rev. It also depends on how close to redline you were when the mis-shift occurred. Did you note how far your VQ revved to?


One of the biggest problems with a big over-rev is a bent valve, or other valvetrain damage. That's something the Z's diagnostic system, or even a compression check may not detect. I doubt sensors or injectors would cause a multiple misfire, but continued misfires under load are not good for a precision built engine like the VQ.
dkmura is offline  
Sponsored Links
Advertisement
 
Reply

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
Replace with
For the best viewing experience please update your browser to Google Chrome