Go Back   Jaguar Forums - Jaguar Enthusiasts Forum > Jaguar Models ( Modern ) > X-Type
Sign in using an external account
Register Forgot Password?
Search

X-Type 2001 - 2009

Welcome to Jaguar Forums!
Welcome to JaguarForums.com.

You are currently viewing our forums as a guest, which gives you limited access to view most discussions and access our other features. By joining our community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join the Jaguar Forums community today!


Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 03-04-2011, 03:43 PM
Junior Member
 
Join Date: Mar 2011
Location: Wasilla, Alaska
Posts: 6
Thanked 0 Times in 0 Posts
Default P0300 Random Misfire

I have a 2002 Jaguar X type. I am getting a P0300 Random Cylinder Misfire Code. This misfire and an accompanying Cruise Not Available is occurring once every 5 miles or so. It happens more frequently when not under load (either idling or when I remove my foot from the gas to decelerate).

I have done the following:

1) replaced all 6 spark plugs with Autolite Dbl Platinum ( I noticed some improvement in driveability when I did this though the problem still occurs).
2) checked all hoses and connections for air intake leaks (found none).
3) ordered replacement ring gaskets for the upper and lower intake tuning valves off of the exhaust manifold as while I did not see or hear a leak they are the original and all the forums say good to replace them.

What is the most likely prognosis?

1) Air leak that I have not found?
2) Faulty Mass Air Flow Sensor?
3) Faulty Ignition coil?
4) Faulty ECU?

What would be the next thing to check ?

Thank you!

John
Reply With Quote
  #2  
Old 03-05-2011, 02:40 PM
Senior Member
 
Join Date: Oct 2007
Location: Pittsburgh, PA
Posts: 206
Thanked 24 Times in 21 Posts
Default

John,

Random misfires are not typical symptoms of a vacuum leak or MAF issue. Bad plug or coil would be my first thought, but the plugs are new and, if it was a coil, I would think (1) you would be getting a misfire code for a particular cylinder, but not random misfires, or (2) you would see even more misfires while under heavy load.

The ECU doesn't sound too likely either because it runs OK under load.

I would check fuel pressure. JTIS claims P300 may be thrown for fuel pressure that is too low or too high.
Reply With Quote
  #3  
Old 03-06-2011, 02:49 PM
Junior Member
 
Join Date: Mar 2011
Location: Wasilla, Alaska
Posts: 6
Thanked 0 Times in 0 Posts
Default Misfire checks

Thank you Mark...you reminded me that I did have this vehicle in the shop quite some time ago and they told me that it looked like it was injecting too much gas into the engine. They said that it sprayed twice per stroke which they did not think that it should be doing.

Is there a way to adjust the fuel pressure?

Thanks.
Reply With Quote
  #4  
Old 03-07-2011, 03:32 PM
Veteran Member
 
Join Date: Nov 2009
Location: Langley, BC
Posts: 1,010
Thanked 51 Times in 47 Posts
Default

I don't think there is a wat to adjust fuel pressure, that is weird that they would say that an injector is firing twice. I'd look in the JTIS to see what actually tells the injector to fire, seems that unit is pooched.
__________________
Previously 2004 X-Type Sport Premium Estate, now Jagless.
Reply With Quote
  #5  
Old 03-07-2011, 09:31 PM
Junior Member
 
Join Date: Mar 2011
Location: norcross ga
Posts: 13
Thanks: 0
Thanked 2 Times in 2 Posts
Default

being a ford engine i would put my money on a bad fuel pressure regulator, or check the hose from the brake booster to the intake manifold, that particular hose has a check valve which is know to deteriorate on the bottom side, its really easy to miss
Reply With Quote
Old 03-07-2011, 09:31 PM
 
 
 
Reply



Tags
2002, autolite, code, cylinders, jaguar, misfire, misfires, missfire, p0300, plugs, po300, random, type, xk8, xtype



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
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


Advertising

Featured Sponsors
Vendor Directory
Our Sponsors
All times are GMT -5. The time now is 11:00 PM.

Copyright © 2010 Internet Brands, Inc. All rights reserved.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014 vBulletin Solutions, Inc. All rights reserved.
JAGUAR and its logo are the registered trademarks of Jaguar Cars Limited. Jaguar Cars Limited is not affiliated with JaguarForums.com.