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Topic Review (Newest First)
09-17-2013 12:34 AM
Shane20 Bump
09-14-2013 09:44 AM
Shane20
Quote:
Originally Posted by Jerry Bransford View Post
I'd bet more on one or both of your upstream 02 sensors being bad, I really doubt your fuel injectors have anything to do with your rough idle.
Thats where I first started. I had a cel light come on showing the bank 2 sensor 1 was bad, so I changed it out but i figured since they were pretty cheap I would replace all of them. since I did that I have had no cel light come on.
09-12-2013 09:38 PM
chevymad All vehicles, though there is some learning done that the ecm applies to the next start.

My jeep ran the same way before and after all 4 new o2 sensors. NTK brand. One cleaning was before changing the sensors and one was after. As said, it runs smooth and quiet after cleaning for about a month.. a little less actually the 2nd time. Runs fine on the road and no check engine light. What I really found interesting was the effect of the pure fuel vs E10.
09-12-2013 11:43 AM
rkulp89
Quote:
Originally Posted by Reznor View Post
Here's the thing about the O2 sensors, and why I ruled them out in my own situation:

Firstly, there is no CEL. This doesn't necessarily mean they are not at least somewhat faulty, but is a good start.

But when a vehicle is first started, it runs in open loop - completely bypassing the O2 sensors until it warms up and then goes into closed loop. So if the idle/running occurs when the vehicle is dead cold, then it shouldn't be the O2 sensors.
I didn't know about the open/closed loop. Does that apply to all vehicles or just jeeps?
09-12-2013 11:02 AM
Reznor Here's the thing about the O2 sensors, and why I ruled them out in my own situation:

Firstly, there is no CEL. This doesn't necessarily mean they are not at least somewhat faulty, but is a good start.

But when a vehicle is first started, it runs in open loop - completely bypassing the O2 sensors until it warms up and then goes into closed loop. So if the idle/running occurs when the vehicle is dead cold, then it shouldn't be the O2 sensors.
09-12-2013 05:49 AM
rkulp89
Quote:
Originally Posted by Jerry Bransford View Post
I'd bet more on one or both of your upstream 02 sensors being bad, I really doubt your fuel injectors have anything to do with your rough idle.
I'm having a rough idle issue that vibrates the cab to the point that the mirrors shake. The engine feels like it stutters every few seconds but never dies. When I hit the gas everything smooths out and runs great. I've cleaned the IAC, swapped plugs, and plan on testing the TPS. Do you think the O2 sensors would be worth changing? I don't understand why the engine is rough while at idle but runs great while driving. I just got the jeep (04 unlimited), not sure if it should be idling like this or not.
09-11-2013 10:31 PM
Jerry Bransford I'd bet more on one or both of your upstream 02 sensors being bad, I really doubt your fuel injectors have anything to do with your rough idle.
09-11-2013 10:15 PM
chevymad My 03 runs a bit rough at idle as well. I've cleaned the injectors twice in the last year and both times it runs much smoother afterwards but it only lasts for a month or so. I've also noticed on a couple trips that if I buy fuel with no ethanol that it will also idle smooth. Eventually I'm going to replace the injectors, since cleaning them does seem to alleviate the issue for awhile.
09-11-2013 11:57 AM
Reznor I'm actually running into a very similar issue on my 03 Sport, though my miss occurs at all times from startup to fully warm. No CEL. I'm debating buying a rebuilt injector set. Have new plugs, new coil, cleaned throttle body, air filter, checked TPS.

If you haven't done that last thing, give it a shot. Easy to do - you can backprobe the connections with a multimeter. The center one is ground, one will have constant 5v(ish) power, and one will move from very low up to around 5v depending on throttle position.
09-11-2013 10:47 AM
Shane20
Quote:
Originally Posted by kdawgg11 View Post
I wish I could help you but I don't know I wonder if there is a air/temp sensor that could do that? I doubt it what about o2 sensor I will think more about it but I am unsure
All foyer o2 sensors are new
09-10-2013 04:48 PM
kdawgg11
Quote:
Originally Posted by Shane20 View Post
Well we had a big temp drop were I live ( roughly 20 degrees colder ) and my jeep was running pretty good. The misfire and rough idle was still there but hardly noticeable. So I wonder what it could be?
I wish I could help you but I don't know I wonder if there is a air/temp sensor that could do that? I doubt it what about o2 sensor I will think more about it but I am unsure
09-10-2013 10:53 AM
Shane20 Well we had a big temp drop were I live ( roughly 20 degrees colder ) and my jeep was running pretty good. The misfire and rough idle was still there but hardly noticeable. So I wonder what it could be?
09-07-2013 03:21 PM
Shane20
Quote:
Originally Posted by kdawgg11 View Post
How is it doing when driving any missing or backfires or doing anything while driving?
well.. it drives great, no rough idle,no mis,nothing
09-07-2013 12:22 PM
kdawgg11
Quote:
Originally Posted by Shane20 View Post
Update: I ended up putting on a new coil ( I dropped it ) and still idling rough.
I'm still thinking it has to do with the fuel injectors.
How is it doing when driving any missing or backfires or doing anything while driving?
09-07-2013 12:11 PM
Shane20 Update: I ended up putting on a new coil ( I dropped it ) and still idling rough.
I'm still thinking it has to do with the fuel injectors.
08-29-2013 02:26 AM
R u s s
Quote:
Originally Posted by Jerry Bransford View Post
I seriously doubt your injectors are dirty, I would bet big $$$ flushing/cleaning the injectors won't help at all.
X2 This guy is a smart cookie

I have yet to see with my own eyes injector cleaner work if its to the point there not spraying right it is time to replace them.
As for your slight miss it could be injector going bad or coil starting to fail. I would lean more toward coil.
Try a different set of plugs. I had an outboard do the same thing and figured out it did not like platinum plugs it ran better with old school no frill spark plugs
08-28-2013 09:48 PM
Shane20 Update: well the idle is still rough. I gapped the plugs again and ran some 44k thou it, and that helped for a little. Still can't seem to pin point the problem. It never stalled out it just seems to me like a misfire. I'm hoping to find the cause soon
08-08-2013 06:43 PM
Shane20
Quote:
Originally Posted by Jerry Bransford View Post
I seriously doubt your injectors are dirty, I would bet big $$$ flushing/cleaning the injectors won't help at all.

Champion 7704 plugs are the wrong model, 7034 is the right double-platinum model Champion spark plug for newer distributorless engines like yours.
I could not remember the number 7034 are what I put in
08-08-2013 09:46 AM
Jerry Bransford I seriously doubt your injectors are dirty, I would bet big $$$ flushing/cleaning the injectors won't help at all.

Champion 7704 plugs are the wrong model, 7034 is the right double-platinum model Champion spark plug for newer distributorless engines like yours.
08-07-2013 11:38 PM
Shane20 Update: took her to a friends shop and scanned it. Well it looked like the voltage didn't change during the misfire to the injectors ( that does not rule out an injector going bad) but it seems like there really dirty according to him, so I'm going to run an injection system flush and see if that helps
08-07-2013 11:30 PM
Shane20
Quote:
Originally Posted by Shelby427 View Post
Not going to say it isn't, but the more common problem with the injector shields was a hot soak problem. After the vehicle was driven, parked for a bit, and then restarted.
Would cause a fuel starvation problem, like vapor lock. Making hard to start, running poorly until enough cool fuel got through the injectors. Can't say I remember it causing a problem in normal driving.

I'm with Jerry, always start with the basics.
I'm using champs 7704 I think. There double plats the dealer sold me
08-07-2013 10:16 PM
Shane20
Quote:
Originally Posted by Shelby427 View Post
Not going to say it isn't, but the more common problem with the injector shields was a hot soak problem. After the vehicle was driven, parked for a bit, and then restarted.
Would cause a fuel starvation problem, like vapor lock. Making hard to start, running poorly until enough cool fuel got through the injectors. Can't say I remember it causing a problem in normal driving.

I'm with Jerry, always start with the basics.
I'm using champs
08-07-2013 08:34 PM
Shelby427 Not going to say it isn't, but the more common problem with the injector shields was a hot soak problem. After the vehicle was driven, parked for a bit, and then restarted.
Would cause a fuel starvation problem, like vapor lock. Making hard to start, running poorly until enough cool fuel got through the injectors. Can't say I remember it causing a problem in normal driving.

I'm with Jerry, always start with the basics.
08-07-2013 01:02 PM
Shane20
Quote:
Originally Posted by xxBOsoxFANxx View Post
I'd go with Jerry on this one (because he helped me through a similar issue). I noticed with mine that I had one plug that was gapped just a hair off and caused my misfire. If it isn't your plugs, it could be a heat soak issue. I had to replace the heat shield under the injectors on mine, old and falling apart. I also placed a sleeve around the number 3 injector. I think there is a thread on here with part numbers. The DIS is very finicky I've come to notice.
Does that sleeve cover the 06 4.0, I thought it was for the 02-04 models
08-07-2013 10:00 AM
xxBOsoxFANxx
Quote:
Originally Posted by Jerry Bransford View Post
Starting with the basics, how old are your spark plugs? If they aren't that old, exactly what brand & model spark plug did you install?
I'd go with Jerry on this one (because he helped me through a similar issue). I noticed with mine that I had one plug that was gapped just a hair off and caused my misfire. If it isn't your plugs, it could be a heat soak issue. I had to replace the heat shield under the injectors on mine, old and falling apart. I also placed a sleeve around the number 3 injector. I think there is a thread on here with part numbers. The DIS is very finicky I've come to notice.
08-06-2013 04:44 PM
Shane20 It's a DIS system
08-06-2013 04:17 PM
James.crawford14 Hmmmm did you look in to your distributer at all
08-06-2013 04:14 PM
Shane20 Update: I went ahead and replaced the IAC and TPS and still did not fix the problem I'm now starting to wonder if my injectors are getting heat soaked
08-06-2013 10:10 AM
Shane20
Quote:
Originally Posted by James.crawford14 View Post
That definitely sounds like your TPS. If it kicks the check engine light take it to an auto parts store for a free test
No mil light. I have a scanner and nothing came up
08-06-2013 10:09 AM
Shane20
Quote:
Originally Posted by Jerry Bransford View Post
Starting with the basics, how old are your spark plugs? If they aren't that old, exactly what brand & model spark plug did you install?
Plugs are champs 7704 put in a couple of days ago. Also put all four new o2 sensors in with NTK brand. I pulled and cleaned the IAC and ran a bottle of 44k in it. Only real weird thing in all that was when I replaced the coil boots and inner springs, the very front boot spring was hard to pull out so I ended up stretching it and it finally came out. I put the new stuff on and they seemed to fit nice so IDK if I my have damaged it.
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