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-   -   WK acting strange... (http://www.jeepgarage.org/f77/wk-acting-strange-25236.html)

tig488 07-02-2011 07:05 PM

WK acting strange...
 
ive had this problem before but it seemed to go away after i changed the EGR. now its back. this only happens for the first 15-30 seconds after a cold start. i crank it, and it drives normal for a few seconds, then starts to buck, stutter and hesitate, especially if i give it gas. instead of let off i go full throttle. it usually goes away after a few seconds then the CEL light flashes and i get a code 0300 which is random misfire. after a few minutes of driving it never does it again. also, ive noticed if i take it out of OD and manual shift, it doesnt do it. maybe tranny fluid, or vac leak?

Escape 07-02-2011 08:06 PM

Re: WK acting strange...
 
Sounds like your front O2 sensors heaters or an electrical connection.

Your Jeep operates in 2 different modes for the fuel injection/engine management.

Open loop = cold start up / WOT / = no sensor input, goes off of last known good operating conditions

Closed loop = after it's warmed up, about 30 seconds or less / normal driving. = sensor input used

In Closed loop the front O2 sensors (bank 1, drivers side / bank 2, passengers side) feed data to the PCM telling it how much fuel to trim/add to get a complete efficient burn cycle. In Open loop it is based off of a set value in the PCM's data tables.

If you have a Diablo Sport Trinity or a DashHawk you can look at what the signals are from your O2 sensors if not you will need a scan tool and a mechanic who is a good friend to help you out.

You could also have a loose electrical connection it will probably be the large gray c-200 connector right next to the fuse boxes under the hood. Unclip it and check for corrosion or debris, clean it with electrical contact cleaner, LET IT DRY then put it back together ensuring a snug fit.

There are also other sensors but these would be the first place I would look.

Hope this helps,
Escape

tig488 07-02-2011 08:25 PM

Re: WK acting strange...
 
thanks escape, i took my diablo out, but ill check out that connector.

lll2for3lll 07-02-2011 09:17 PM

Re: WK acting strange...
 
Sounds like you need you PCM flashed. I had the same issues.

lll2for3lll 07-02-2011 09:19 PM

Re: WK acting strange...
 
I never got the light though.

I'd say replaced trans fluid and flash the PCM.

tig488 07-04-2011 03:06 PM

Re: WK acting strange...
 
i fooled with the plug, didnt do anything. it only does it while cold, when the engine warms up, its fine. also, it only seems to do it in OD, doesnt happen if i manual shift. gonna add some tranny fluid today. and reset the ecu. then maybe a pcm reflash.

tig488 07-07-2011 09:56 PM

Re: WK acting strange...
 
finally said F*** it. pisses me off so bad when it happens that I downshift to 1st and redline it just hoping it will blow.

i disconnected the EGR today, have a CEL. gonna see if that changes anything. if it does help, i can live with a CEL.

Escape 07-07-2011 11:50 PM

Re: WK acting strange...
 
What engine does it have? What year is it? How old is the battery?

tig488 07-08-2011 12:21 PM

Re: WK acting strange...
 
05, 5.7L, just hit 100K miles. starter replaced 2 months ago, battery probably a year old, EGR replaced 20K miles ago, plugs replaced at 60K. stock plug wires and 02 sensors still. i dont think i have a vacuum leak but its possible.

it drove great today with the EGR unplugged. ill see how it does over the weekend. ill probably add some tranny fluid and do an ECU reset too.

its hard to describe what it does and it doesnt do it everytime, id say 1 in 4 cranks it stutters and feels like there is no throttle response for about 30 seconds. say i pull up to a stop sign and apply the brakes, it stumbles and stutters. it doesnt die just acts like it will. i have to really give it gas to make it go. then after it warms up its fine.

tig488 07-10-2011 11:39 AM

Re: WK acting strange...
 
dont wanna jinx myself, but unplugging the EGR seemed to have fixed it. i have a CEL, but it runs like new again. similar to when i replaced the EGR. no stutter, no eratic idle, no hesitation. acceleration is back and smooth again. stupid EGR, is should have just unplugged it years ago. gas mileage is the same.

Escape 07-10-2011 11:30 PM

Re: WK acting strange...
 
You can make a block off plate and seal off the EGR unit in place. Thereby leaving it plugged in and not having any codes or get a complete delete kit and turn it off with a CMR tune.

tig488 07-11-2011 09:43 AM

Re: WK acting strange...
 
thats what im in the process of doing. ill see how it runs for a few more days and decide but as of today it still runs great.

i cant decide if i want to keep it plugged in with it blocked off, im worried it will cause the ecu to make fuel/timing adjustments and not have the EGR working. i think i might just keep it unplugged and live with the CEL.


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