How to tell if a ignition coil is going bad - Page 2 - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > WJ Grand Cherokee Forum > How to tell if a ignition coil is going bad

Thanksgiving/Black Friday/Cyber Monday Deals at JeepinOutfIntroducing MONSTALINER™ UV Permanent DIY Roll On Bed LineBlack Friday- Cyber Monday Deals at jeepHut

Reply
Unread 05-30-2014, 11:52 AM   #16
outofrng623
Registered User
2004 WJ 
 
Join Date: Aug 2012
Location: yonkers, ny
Posts: 517
Quote:
Originally Posted by Gunrunner23 View Post
It's not THAT rough. Just not steady. But dips down to 350-400 rpm at some stops.
I know this thread is really old...just curious, did you resolve the issue? I have the same problem and horrible mileage (8mpg calc by hand)...I have gone through a lot of stuff to no avail. Thanks

outofrng623 is offline   Reply With Quote Quick reply to this message
Unread 07-18-2014, 05:44 AM   #17
Gunrunner23
Registered User
2004 WJ 
 
Join Date: May 2012
Location: Knoxville, TN
Posts: 866
Quote:
Originally Posted by outofrng623 View Post

I know this thread is really old...just curious, did you resolve the issue? I have the same problem and horrible mileage (8mpg calc by hand)...I have gone through a lot of stuff to no avail. Thanks
I've had a friend with the same problem replace some o2 sensors and it fixed it. I don't have the money to throw down on o2 sensors right now so unjust live with it. Even though it's throwing a code for o2 sensor....

Recently after I start my wj, then drive for a bit and when I come to my first stop light it acts like it's gonna die when it's down shifting. It seems to only do any of this low rpm crap after down shifting. Like if I'm at a stop light and it goes down to 350-400 and I gas it a bit it will not drop back down again. Sometimes it will even correct itself.

I just live with it since its pretty common but not many people have fixed it. Aside from o2 sensors, transmission speed sensor, or clogged cat. But there have been people that have done the above and it didn't fix it so Idk.
__________________
2004 wj limited 4.7
IRO 3in lift with skyjacker hydro
265/75/16 TreadWright Claws
Gunrunner23 is offline   Reply With Quote Quick reply to this message
Unread 07-18-2014, 07:34 AM   #18
outofrng623
Registered User
2004 WJ 
 
Join Date: Aug 2012
Location: yonkers, ny
Posts: 517
I have the same issues. Threw a lot of new things at it including o2s mopar. I am getting horrible mileage, stall maybe once every two months, just sitting idle even. Sometimes I idle at 700 sometimes 500. No logic. I've replaced the tps, iac, plugs, coils, exhaust including cats. No change. Fixed an exhaust leak. Still throw p0420 code, maybe another leak that wasn't seen? When it started happening I put in new o2s, three weeks later, same thing.
outofrng623 is offline   Reply With Quote Quick reply to this message
Unread 07-18-2014, 07:40 AM   #19
Gunrunner23
Registered User
2004 WJ 
 
Join Date: May 2012
Location: Knoxville, TN
Posts: 866
There's actually a reflash that I have read that helps. Some dealers do it free some don't. All of mine were going to charge me way too much. So F it.

Have u checked Ur injectors?

Fuel pressure?
__________________
2004 wj limited 4.7
IRO 3in lift with skyjacker hydro
265/75/16 TreadWright Claws
Gunrunner23 is offline   Reply With Quote Quick reply to this message
Unread 07-18-2014, 12:23 PM   #20
outofrng623
Registered User
2004 WJ 
 
Join Date: Aug 2012
Location: yonkers, ny
Posts: 517
Fuel pressure has been checked and is fine. New pump as well. Injectors and compression are the only two things that haven't been done.
I find it odd that it only started after Having the exhaust done.
I've also heard about the reflash from a few people but see nothing in any of the tsbs for my year/engine. It also happened after I got the jeep, wasn't at acquisition. So if it needed a flash I would think it would've been a problem from day one. Maybe the actual PCM is going?
outofrng623 is offline   Reply With Quote Quick reply to this message
Unread 07-18-2014, 12:42 PM   #21
Gunrunner23
Registered User
2004 WJ 
 
Join Date: May 2012
Location: Knoxville, TN
Posts: 866
I'm not quite sure the reflash was really advertised. But I'm not guite sure. I've read that it's something that eventually needs to be done.
__________________
2004 wj limited 4.7
IRO 3in lift with skyjacker hydro
265/75/16 TreadWright Claws
Gunrunner23 is offline   Reply With Quote Quick reply to this message
Unread 07-19-2014, 08:52 PM   #22
outofrng623
Registered User
2004 WJ 
 
Join Date: Aug 2012
Location: yonkers, ny
Posts: 517
There's a guy around me that does it for 125 I think. I also know an owner of a dealership, maybe he can get it done for me for nothing. I'll see. If I have to pay, I may be better off just getting a new PCM.
outofrng623 is offline   Reply With Quote Quick reply to this message
Unread 07-19-2014, 09:31 PM   #23
Gunrunner23
Registered User
2004 WJ 
 
Join Date: May 2012
Location: Knoxville, TN
Posts: 866
I'm pretty certain the tsb reflash will fix it.
__________________
2004 wj limited 4.7
IRO 3in lift with skyjacker hydro
265/75/16 TreadWright Claws
Gunrunner23 is offline   Reply With Quote Quick reply to this message
Unread 07-20-2014, 07:13 AM   #24
outofrng623
Registered User
2004 WJ 
 
Join Date: Aug 2012
Location: yonkers, ny
Posts: 517
I just find it odd that it started happening after the exhaust was done...have had mileage issues for two years now...
outofrng623 is offline   Reply With Quote Quick reply to this message
Unread 07-20-2014, 07:45 AM   #25
Gunrunner23
Registered User
2004 WJ 
 
Join Date: May 2012
Location: Knoxville, TN
Posts: 866
That is weird although I can't see anything that would be a problem. I man aside from o2 sensors down there. You didn't put like 5inch pipes in did ya? Lol
__________________
2004 wj limited 4.7
IRO 3in lift with skyjacker hydro
265/75/16 TreadWright Claws
Gunrunner23 is offline   Reply With Quote Quick reply to this message
Unread 07-20-2014, 12:38 PM   #26
rm2001wj
Web Wheeler
 
rm2001wj's Avatar
2001 WJ 
 
Join Date: Aug 2005
Location: Memphis, TN
Posts: 3,119
Quote:
Originally Posted by outofrng623 View Post
I just find it odd that it started happening after the exhaust was done...have had mileage issues for two years now...
There is supposed to be a braided ground cable fastened to the exhaust system (somewhere near the cat or muffler IIRC). Did it get left off?
__________________
2001 WJ Limited with Quadra-Drive, Kenne Bell Supercharger, 3-inch Kolak exhaust, Stillen rotors (F/R) and MM pads, Addco sway bars (F/R).
rm2001wj is offline   Reply With Quote Quick reply to this message
Unread 07-20-2014, 06:32 PM   #27
Gunrunner23
Registered User
2004 WJ 
 
Join Date: May 2012
Location: Knoxville, TN
Posts: 866
Quote:
Originally Posted by rm2001wj View Post
There is supposed to be a braided ground cable fastened to the exhaust system (somewhere near the cat or muffler IIRC). Did it get left off?
Mine came loose and was all rusted. It did all of the above. Before it got loose and I cut it off. I never reconnected mine so maybe, but it is a well known 4.7 problem. So surely it can't be one ground wire but ya never know!!
__________________
2004 wj limited 4.7
IRO 3in lift with skyjacker hydro
265/75/16 TreadWright Claws
Gunrunner23 is offline   Reply With Quote Quick reply to this message
Unread 07-21-2014, 04:29 AM   #28
outofrng623
Registered User
2004 WJ 
 
Join Date: Aug 2012
Location: yonkers, ny
Posts: 517
Took a look. Looks like the wonderful shop that did my exhaust neglected to put it back on. Not trying to be a Wiseass but is it really a known problem for the o2s and would throw this code and I have to wonder why only the one side. I'll see if there's enough to reattach otherwise I'll have to see if I can buy another one (I had replaced it once already) or make one. Ugh
outofrng623 is offline   Reply With Quote Quick reply to this message
Unread 07-21-2014, 05:50 AM   #29
Gunrunner23
Registered User
2004 WJ 
 
Join Date: May 2012
Location: Knoxville, TN
Posts: 866
Quote:
Originally Posted by outofrng623 View Post
Took a look. Looks like the wonderful shop that did my exhaust neglected to put it back on. Not trying to be a Wiseass but is it really a known problem for the o2s and would throw this code and I have to wonder why only the one side. I'll see if there's enough to reattach otherwise I'll have to see if I can buy another one (I had replaced it once already) or make one. Ugh
Well I should of clarified. The low idle is a known problem with the 4.7 with several different claimed fixes. Which are listed above. The reflash seems to be the end all fix; in other forums as well.
__________________
2004 wj limited 4.7
IRO 3in lift with skyjacker hydro
265/75/16 TreadWright Claws
Gunrunner23 is offline   Reply With Quote Quick reply to this message
Unread 07-21-2014, 08:36 PM   #30
outofrng623
Registered User
2004 WJ 
 
Join Date: Aug 2012
Location: yonkers, ny
Posts: 517
Two round trip drives this week that would normally trigger the p0420...Did not. The only differences are, I put in a new battery (yes I have disconnected and reset prior to changing), so its not the reset, maybe the voltage...and I disconnected my obd2 scanner.
outofrng623 is offline   Reply With Quote Quick reply to this message
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.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

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.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.