Misfire and check engine light-flashes 12 times

For issues like this you need an auto electrician with a pro grade bi-directional scan tool computer to diagnose. The misfire may just be spark plug condition, but it could be a sensor issue. It is better to pay a pro and only change the parts that need it rather than 'let's try replacing this' method of repair.

Just change/replace that one injector. That's causing the misfire. Don't let anybody tell you the head has to come off and a valve replaced, just change the #1 injector.

Check Engine Light/Misfire Due to Intake Valve Locks ...

repairpal.com > Problems > Jeep > Liberty

Jeep Liberty Check Engine Light/Misfire Due to Intake Valve Locks/Valves. ...Misfire cyc 4 and random cyc misfires, changed coil packs and plugs... sounds as if rod ... Light came on again (misfire on cylinder 4) - switched coil from 4 to 2. Light ...

Jeep Liberty Questions - Cylinder Misfire code - CarGurus

www.cargurus.com > Questions > Jeep > Liberty

CarGurusMay 27, 2009 - #4 misfire new plugs and coil pack on #4 light came back on after 300 miles if ... How come it stopped misfiring for 2-3 months, and now is back? ... I have a 2005 Jeep Liberty 6 cylinder, engine light came on scaned the codes ...

Liberty Cylinder Misfire / Computer issue? - JeepForum.com

These use seperate coil packs for each cyl. and I think you have a bad coil pack on that cyl

The engine and the automatic transmission in this vehicle are computer controlled and in most cases when a fault occurs a fault code is stored in the memory of the computer control module. There are exception to this, such as the Mass Airflow Meter and fuel pressure problems. What must be done is to have all the basic testing done such as a scan of the system for fault codes as well as a check with a live data scanner tool for engine functions that are not within range of normal, a trained technician is required to know what is correct and what isn't, then based on careful diagnostics done from a factory repair manual the correct part is replaced or the wiring repaired or the computer replaced (known as the PCM), which is very rarely the problem. Other basic checks must be done as well such as mechanical problems with the engine as well as engine state of tune and mileage on the engine. The transmission can have mechanical issues as well such as no gear engagement at all or a failed pump or other pressure related problems.

For engine misfiring problem check the help links mentioned below. Click the link below to go through the troubleshooting procedure :---- Engine misses and truck jumps? Hard to down shift? Issue with high gear only? http://technoanswers.blogspot.in/2012/02/engine-miss-and-truck-jumps-hard-to.html

-----------
Bad miss at idle?

http://technoanswers.blogspot.com/2012/01/bad-miss-at-idle.html

-----------
While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

------------
Engine Misfire codes for car?

http://schematicsdiagram.blogspot.com/2011/12/engine-misfire-codes-on-chevrolet.html
Engine Misfire codes?

http://schematicsdiagram.blogspot.com/2011/12/engine-misfire-codes-on-chevrolet.html

--------------
Misfire on cylinder 4?

http://schematicsdiagram.blogspot.com/2011/12/misfire-on-cylinder-4.html

-----------
Oil on spark plugs and car misfires?

http://technoanswers.blogspot.in/2012/02/oil-on-spark-plugs-and-car-misfires.html

----------

This will help.

Thanks.

I would start with plug wires rubbing on something and created a short.and is not compleatly worn through. a cheep place to start. good luck with it.

those are misfire codes. Cylinder #1 & #2 in the firing order. Check for bad plugs first. Swap one of the misfires with a non misfire cylinder and see if that cylinder misfires. Or just change the 2 plugs. Put high temp anti seize on the threads if you ever want to remove them later.

Then change the 2 COPs (Coil on Plug).

Finally, check for plugged or bad injectors. CHevron Techron injector cleaner is the best. Add to 1/4 tank of gas for better cleaning.

Report results.

Please rate too. Thanks.

well the first thing you should do is check the compression in cyl number four the compression should be within 5-8 of the nearest cyl if you see a significant diffrence in pressure you have a week cylinder...also is there any discoloration on the number 4 spark plug a coolant soaked or fuel soaked spark plug can lead u in the right direction..lastly i would take a look at the exact fuel pressure you will need a gauge and take a look low or high fuel pressure can cause a misfire....keep in mind that a clogged catylitic convertor can also cause a misfire do to accesive back pressure give your convertor a tap and see if its rattling ....hopefully this can lead u in the right direction ...good luck

there may be a software update for the powertrain control module for mis-fire monitor. check with your local dealer. but if thats not the case,these engines are known at least in my experience of having the heads crack between the valves and cause mild mis-fires. try compression testing all the cylinders and performing a leakdown test on them as well.