P0300 random misfire code, at the same time transmission over temp. Please help!!! - JeepForum.com

 
LinkBack Thread Tools
post #1 of 8 Old 12-02-2013, 06:44 PM Thread Starter
Jam1869
Registered User
 
Join Date: Dec 2013
Location: Charlottesville
Posts: 4
P0300 random misfire code, at the same time transmission over temp. Please help!!!

Hi all, the other day my Wk suddenly starting to show an overheating vehicle, and as I turned off "transmission over temp" showed up in my display. Afterwards, I had trouble starting my car, finally getting the engine to turn over after twenty minutes or so. Check engine light signaled a random misfire code (p0300). I immediately changed my spark plugs as they were pretty old, and the problem seemed to be fixed. Lo and behold, three days later the ignition trouble started again. Transmission signal showing up as well. Either it's a huge coincidence or these problems are somehow related. Could someone please help?

Thanks so much in advance for any advice anyone can provide.

Jam1869 is offline  
Sponsored Links
Advertisement
 
post #2 of 8 Old 12-02-2013, 06:57 PM
Walt
Registered User
2008 WK 
 
Join Date: Oct 2009
Location: Midland
Posts: 1,559
Need more info to help.....model year / engine / drivetrain / maintenance status / etc.

Recommend you fill out your profile with this data.

HEMI CLUB MEMBER #45; SILVER WK CLUB MEMBER #13
'08 WK GC Limited. 5.7L HEMI. Quadra-Trac II. Bright Silver Metallic. Class IV hitch.
Michelin LTX M/S tires. Fumoto oil drain valve. Billet Technology oil catch can.
Walt is offline  
post #3 of 8 Old 12-02-2013, 08:27 PM Thread Starter
Jam1869
Registered User
 
Join Date: Dec 2013
Location: Charlottesville
Posts: 4
Quote:
Originally Posted by Walt
Need more info to help.....model year / engine / drivetrain / maintenance status / etc.

Recommend you fill out your profile with this data.
2006 Laredo, 2wd, 3.7L V6, 137k miles, fresh oil change
Jam1869 is offline  
post #4 of 8 Old 12-03-2013, 04:17 PM Thread Starter
Jam1869
Registered User
 
Join Date: Dec 2013
Location: Charlottesville
Posts: 4
Update: When I stop and go idle, fluid starts to leak and noise comes from glove box area. Also, cold starts are not an issue.
Jam1869 is offline  
post #5 of 8 Old 12-03-2013, 07:04 PM
Walt
Registered User
2008 WK 
 
Join Date: Oct 2009
Location: Midland
Posts: 1,559
Quote:
Originally Posted by Jam1869 View Post
Update: When I stop and go idle, fluid starts to leak and noise comes from glove box area. Also, cold starts are not an issue.
I do not have a 3.7L V-6. However, it sounds like a leaking heater core. Check the leaking fluid to see if it is somewhat slippery, pink, and smells sweet. DO NOT TASTE IT as ethylene glycol is highly poisonous.

You can do a cooling system pressure test to see if there is a pressure boundary breach somewhere. Radiator cap is stamped with the system pressure, so you know the psig to apply. If there is a leak, I would expect that the coolant overflow tank level would be dropping also. Another thing to check.

Likely your coolant is MOPAR HOAT (Hybrid Organic Acid Technology), so care must be taken for a compatible replacement.

When you get through, you might consider a new radiator cap if it over 6 yrs. old. The springs get weak and fail to hold cooling system pressure. Think they run ~$7.

My 2 cents worth. Caution: This advice may be worth what you paid to get it!

HEMI CLUB MEMBER #45; SILVER WK CLUB MEMBER #13
'08 WK GC Limited. 5.7L HEMI. Quadra-Trac II. Bright Silver Metallic. Class IV hitch.
Michelin LTX M/S tires. Fumoto oil drain valve. Billet Technology oil catch can.
Walt is offline  
post #6 of 8 Old 12-03-2013, 09:50 PM Thread Starter
Jam1869
Registered User
 
Join Date: Dec 2013
Location: Charlottesville
Posts: 4
Quote:
Originally Posted by Walt

I do not have a 3.7L V-6. However, it sounds like a leaking heater core. Check the leaking fluid to see if it is somewhat slippery, pink, and smells sweet. DO NOT TASTE IT as ethylene glycol is highly poisonous.

You can do a cooling system pressure test to see if there is a pressure boundary breach somewhere. Radiator cap is stamped with the system pressure, so you know the psig to apply. If there is a leak, I would expect that the coolant overflow tank level would be dropping also. Another thing to check.

Likely your coolant is MOPAR HOAT (Hybrid Organic Acid Technology), so care must be taken for a compatible replacement.

When you get through, you might consider a new radiator cap if it over 6 yrs. old. The springs get weak and fail to hold cooling system pressure. Think they run ~$7.

My 2 cents worth. Caution: This advice may be worth what you paid to get it!
Thanks for the advice...it's actually green so coolant I'm guessing. Also worthy of noting is that the heater is blowing cold air in my cabin. So we have random misfires, external coolant leak, trouble starting a warm engine, engine getting hot in idle. Gasket?

I may get berated for this, but if I'm planning to only keep this vehicle for another few months, is Stop Leak a viable thing to try as a sort of catch-all?
Jam1869 is offline  
post #7 of 8 Old 12-04-2013, 03:30 PM
Walt
Registered User
2008 WK 
 
Join Date: Oct 2009
Location: Midland
Posts: 1,559
Quote:
Originally Posted by Jam1869 View Post
Thanks for the advice...it's actually green so coolant I'm guessing. Also worthy of noting is that the heater is blowing cold air in my cabin. So we have random misfires, external coolant leak, trouble starting a warm engine, engine getting hot in idle. Gasket?

I may get berated for this, but if I'm planning to only keep this vehicle for another few months, is Stop Leak a viable thing to try as a sort of catch-all?
One of the 3.7L V-6 guys will have to opine on the starting/running issues. Head gasket failure would likely show up as hard starting cold and rough running until it burns off. You would see oil in the coolant and/or water in the lube oil.

Stop leak may work, depending on hole size. Probably fail on first hot day next summer. Try to look in the area of the leak to see if there is a hose connection to tighten or can be wrapped/patched easily.

Blowing cold air sounds like a blend door. However, if the heater core is not full of coolant (for instance, an air bubble from a partially full system), it will not transfer heat effectively. I would touch this symptom until after the cooling system leak is rectified, the coolant system is burped of air, and it holds rated pressure/temperature.

HEMI CLUB MEMBER #45; SILVER WK CLUB MEMBER #13
'08 WK GC Limited. 5.7L HEMI. Quadra-Trac II. Bright Silver Metallic. Class IV hitch.
Michelin LTX M/S tires. Fumoto oil drain valve. Billet Technology oil catch can.
Walt is offline  
post #8 of 8 Old 12-04-2013, 04:17 PM
johngreen1234
Registered User
2010 WK 
 
Join Date: Nov 2012
Location: beverly hills
Posts: 460
Just to repeat what Walt said, if the coolant is green you have the wrong coolant in there.
johngreen1234 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



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