P300, P301,P302,P304,P305,P306 misfire error codes - JeepForum.com

 
LinkBack Thread Tools
post #1 of 15 Old 07-05-2010, 06:51 PM Thread Starter
aziziy
Registered User
 
Join Date: Dec 2008
Location: potsdam,ny
Posts: 24
P300, P301,P302,P304,P305,P306 misfire error codes

Hello,
I have a 2001 jeep grand Cherokee V6. It runs great and I don't have any problem with it. Yesterday the check engine light came on (while I was driving in highway) and when I check it it gave me P300, P301,P302,P304,P305,P306 misfire error codes.
I don't have any problem with my jeep though. I had changed my spark plugs last summer.
Do you have any suggestion what's going on with my jeep?
Thanks a lot in advance.
Joe

aziziy is offline  
Sponsored Links
Advertisement
 
post #2 of 15 Old 07-05-2010, 06:54 PM Thread Starter
aziziy
Registered User
 
Join Date: Dec 2008
Location: potsdam,ny
Posts: 24
I got 96000 miles on my jeep.
aziziy is offline  
post #3 of 15 Old 07-05-2010, 09:46 PM
kentman
Registered User
 
kentman's Avatar
2006 XK Commander 
 
Join Date: Jan 2004
Location: Wilmington, NC
Posts: 1,437
Garage
I would check the fuel pressure at the rail. Fuel pump could be going out.

'06 XK Limited, 5.7L, QD II, Black, 155K
'02 WJ Overland, 4.7L HO, QD, Inferno Red, 118K
kentman is offline  
post #4 of 15 Old 07-06-2010, 06:17 AM
ratmonkey
R.I.P.
 
ratmonkey's Avatar
1997 ZJ 
 
Join Date: Dec 2006
Posts: 19,793
what plugs did you use? rechecked the gap? fuel pressure? how's the mileage been? abnormally low or high? how are your engine grounds?

btw it's an INLINE six not a V6.

'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

ratmonkey is offline  
post #5 of 15 Old 07-06-2010, 08:26 AM Thread Starter
aziziy
Registered User
 
Join Date: Dec 2008
Location: potsdam,ny
Posts: 24
Car dealer replaced my plugs so I think it should be a platinum one. Gas mileage is normal (like it used to be). When engine is hot when I start the engine I can feel some vibration in engine which I think is misfiring. I'll check the pressure though.
Thanks
aziziy is offline  
post #6 of 15 Old 07-06-2010, 01:13 PM
jamtoy
Registered User
2001 WJ 
 
Join Date: Jun 2004
Location: Boardman, OH
Posts: 190
Crank Position Censor. Common problem and will throw those codes. Went through three on mine. Get a good one or you will be changing it again. I also found that any bad gas will do the same. Reset the pcm and all is well.

Mine also has the hot start roughness. Only does it when the air conditioning is on. Which in this heat is all the time.
jamtoy is offline  
post #7 of 15 Old 07-06-2010, 01:47 PM Thread Starter
aziziy
Registered User
 
Join Date: Dec 2008
Location: potsdam,ny
Posts: 24
Thanks!
I reset the codes and they never came back. So I think this codes show up as I am driving in high way (60-70 mph). But in town I don't have such problem and I won't get any error code.
So it seems that something is going on while I am driving fast. I'll check PCM and fuel filter though.
aziziy is offline  
post #8 of 15 Old 07-06-2010, 07:24 PM
kentman
Registered User
 
kentman's Avatar
2006 XK Commander 
 
Join Date: Jan 2004
Location: Wilmington, NC
Posts: 1,437
Garage
The codes will probably return. I had similar issues a couple years ago on the WJ. I had to swap a few injectors for new. I think that a tank of Sunoco Ultra 94 octane in Florida started my issues.

'06 XK Limited, 5.7L, QD II, Black, 155K
'02 WJ Overland, 4.7L HO, QD, Inferno Red, 118K
kentman is offline  
post #9 of 15 Old 07-06-2010, 08:08 PM Thread Starter
aziziy
Registered User
 
Join Date: Dec 2008
Location: potsdam,ny
Posts: 24
did you get misfire error for some cylinder or just some of them? which injector do I have to replace?
aziziy is offline  
post #10 of 15 Old 07-06-2010, 10:45 PM
kentman
Registered User
 
kentman's Avatar
2006 XK Commander 
 
Join Date: Jan 2004
Location: Wilmington, NC
Posts: 1,437
Garage
I started with 304. That moved on to 308. I think that I had 300 at one point. I replaced injectors 2, 4, and 8 if I remember correctly. It seemed like my issues were more on the passenger side of the fuel rail. Since you are getting multiple codes, it sounds more like fuel pump rather than individual injectors. Just a hunch.

'06 XK Limited, 5.7L, QD II, Black, 155K
'02 WJ Overland, 4.7L HO, QD, Inferno Red, 118K
kentman is offline  
post #11 of 15 Old 05-18-2015, 12:41 PM
PoWdA
Registered User
2000 XJ Cherokee 
 
Join Date: May 2015
Location: Littleton
Posts: 56
Folks,

I am getting 300, 303, and 304. the 300 fired twice. From what I understand 303 and 304 are individual cylinder failures and 300 is a multi-cylinder failure. As far as fuel economy goes... Oh my god this jeep eats gas like it does not care. I bought the Jeep last week. It is my first Jeep. I expected bad fuel economy but this is nuts. Any ideas where to start on mine?

2000 Cherokee. 174k miles.
PoWdA is offline  
post #12 of 15 Old 05-18-2015, 02:28 PM
BigPhil722
Registered User
2001 WJ 
 
Join Date: Mar 2015
Location: cottonwood heights
Posts: 54
I was having similar issues with my 01 limited. I changed plugs and checked TPS, CPS and a few other things that I read could cause those misfire problems. Finally after weeks, I realized that this was happening on the highway, and when my jeep got really hot. I think the exhaust manifold was heating my injectors making my check engine light come on. Anyway, wrapped my fuel rails, and now no CEL. Also, this link on here is very helpful http://www.jeepforum.com/forum/f310/...guide-2212697/
BigPhil722 is offline  
post #13 of 15 Old 05-18-2015, 02:55 PM
PoWdA
Registered User
2000 XJ Cherokee 
 
Join Date: May 2015
Location: Littleton
Posts: 56
Quote:
Originally Posted by BigPhil722 View Post
I was having similar issues with my 01 limited. I changed plugs and checked TPS, CPS and a few other things that I read could cause those misfire problems. Finally after weeks, I realized that this was happening on the highway, and when my jeep got really hot. I think the exhaust manifold was heating my injectors making my check engine light come on. Anyway, wrapped my fuel rails, and now no CEL. Also, this link on here is very helpful http://www.jeepforum.com/forum/f310/...guide-2212697/
Great link!

The best part of this whole scenario is the light came on during emissions testing. Bought the Jeep nearly two weeks ago and it never had a light. Emissions facility takes my Jeep in and it comes out on the other side with a check engine light. So this raises the question, are they liable?

I can say that the Jeep had a rough start. It seems like sometimes when I fire it up it has a very rough idle that eventually smooth's itself out. Is this the hot rough start I am hearing about? I am new to these Jeeps and am learning a lot.
PoWdA is offline  
post #14 of 15 Old 06-02-2015, 08:17 AM
PoWdA
Registered User
2000 XJ Cherokee 
 
Join Date: May 2015
Location: Littleton
Posts: 56
Quote:
Originally Posted by PoWdA View Post
Folks,

I am getting 300, 303, and 304. the 300 fired twice. From what I understand 303 and 304 are individual cylinder failures and 300 is a multi-cylinder failure. As far as fuel economy goes... Oh my god this jeep eats gas like it does not care. I bought the Jeep last week. It is my first Jeep. I expected bad fuel economy but this is nuts. Any ideas where to start on mine?

2000 Cherokee. 174k miles.
So a couple of weeks ago I changed the spark plugs and reset the code. It came back yesterday. I have noticed that both times I have gotten the codes it was after a rough start. Basically when I start up the Jeep sometimes it starts very rough and struggles for 10-20 seconds to stay running. Starter turns and it fires right up but then idles really bad for 10-20 seconds until it seems to find it's rhythm. So, it appears that it is misfiring on start up and that is when it is throwing the codes. Any ideas on this rough start?
PoWdA is offline  
post #15 of 15 Old 01-21-2016, 11:15 AM
ghoward3
Registered User
 
Join Date: Jan 2016
Posts: 1
here's a quick fix. unscrew the gas cap and hold it about 6 inches from the gas fill tube...holding it level and steady. have your wife back another car up to the gas cap, (preferrably not a jeep). put gas cap on the new car, fixed! special side note: Sometimes the gas cap needs to be replaced also because it came from a jeep.
ghoward3 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
05 WK 4.7L Misfire - no PCM codes 05_WK_NH WK Grand Cherokee & XK Commander Forum 19 03-16-2010 06:47 AM
P0300, and P0301-P0306 misfire codes jfl564 ZJ Grand Cherokee Forum 5 12-06-2009 03:35 PM
Error codes 19wj99 ZJ Grand Cherokee Forum 4 04-24-2009 08:03 PM
misfire codes...Spark plugs? GrandJC78 ZJ Grand Cherokee Forum 0 10-07-2008 05:18 PM
Misfire trouble codes...any suggestions? tp2txh ZJ Grand Cherokee Forum 9 10-29-2006 07:51 AM

Posting Rules  
You may post new threads
You may 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 Off
Pingbacks are On
Refbacks are On

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