We have a 2008 jeep commander, check engine light is on. ran a diagnostic because of engine noise, it said cylinder 4 misfire. so far we replaced the or, sparkplug, and coil for cylinder 4, it still h

It's probably a coil breaking down , have a scan tool hooked up an have misfires checked to see which cylinder is missing .
Ignition Coils
Each ignition coil has an ignition 1 voltage feed and a ground. The engine control module (ECM) supplies a low reference and an ignition control (IC) circuit. Each ignition coil contains a solid state driver module. The ECM will command the IC circuit ON, this allows the current to flow through the primary coil windings for the appropriate time or dwell. When the ECM commands the IC circuit OFF, this will interrupt current flow through the primary coil windings. The magnetic field created by the primary coil windings will collapse across the secondary coil windings, which induces a high voltage across the spark plug electrodes. The coils are current limited to prevent overloading if the IC current is held high too long. The spark plugs are connected to their respective coils by a short secondary wire. The spark plugs are tipped with iridium for long life and efficiency.
Drive it long enough like that (with it misfiring ) the check engine light will flash . This is to warn that a catalytic converter damaging event is taking place . This would also set a DTC - diagnostic trouble code
DTC Descriptors ?€¢
DTC P0300 Engine Misfire Detected

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DTC P0301 Cylinder 1 Misfire Detected

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DTC P0302 Cylinder 2 Misfire Detected

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DTC P0303 Cylinder 3 Misfire Detected

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DTC P0304 Cylinder 4 Misfire Detected

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DTC P0305 Cylinder 5 Misfire Detected

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DTC P0306 Cylinder 6 Misfire Detected

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DTC P0307 Cylinder 7 Misfire Detected

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DTC P0308 Cylinder 8 Misfire Detected

2003 Jeep Liberty- Reading Engine / Diagnostic Codes ...

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Jan 6, 2013 - Uploaded by DeathScouter
2003 Jeep Liberty- Reading Engine / Diagnostic Codes ..... error code will flash 2 times, brief pause, flash 1 time, pause, flash 5times, pause, ...

2005 Jeep Liberty possible cause of P0442 error. - YouTube

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Dec 21, 2014 - Uploaded by TheBGravit
While replacing a bad fuel pump I believe I found the cause of a P0442 Error code. I was able to repair the ...

Jeep Liberty Questions - Cylinder Misfire code - CarGurus

www.cargurus.com > Questions > Jeep > Liberty

CarGurusMay 27, 2009 - My jeep Liberty 2009 does the same the Dashboard showed a code of cylinder .... i have a jeep liberty 2006 with the # 5 cylinder misfire. i replaced the sparks... I have a 2005 Jeep Liberty 6 cylinder, engine light came on scaned the ... 2002 jeep liberty camshaft posistion sensor error code p0340 5 answers.

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

repairpal.com > Problems > Jeep > Liberty

Recently got a second hand 2005 Jeep Liberty Sport. Everything worked fine ... #5intake valve seat dropped and held open the intake valve. 2008 Jeep Liberty.

OBD-II Trouble Code: P0305 Cylinder 5 Five Misfire Detected

www.obd-codes.com/p0305

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

Sounds like a ECU problem. The main computer. Take it to a Hyundai dealership and have them check the computer. You don't say how many cylinders if the cylinders are next to each other could have engine or gasket damage

sounds like they have done a good job, save up your money, wont be cheap most likely

take it back to the dealer they didnt install the coil or electric distubutor properly because of the misfire its causes o2 sensor to give bad reading .

IT could be something such as a loose plug wire.The best advise I can give you is to take your jeep to your local auto parts store and have them pull the codes out of your on board computer.This will give you an area that you can concentrate on to make the necessary repairs to get your check engine light to go out.

The only way, for shure is to go to computer diagnostics. 99% sure that this is some engine sensor, buy only diagnostics will tell who. (130,000 miles, hm lamda. it have only 150,000km live)

P0300 Code - Random Misfire

Symptoms Symptoms may include:

• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present

Causes A code P0300 may mean that one or more of the following has happened:

• Faulty spark plugs or wires
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector(s)
• Burned exhaust valve
• Faulty catalytic converter(s)
• Stuck/blocked EGR valve / passages
• Faulty camshaft position sensor
• Defective computer

Check intake gasket and vecuum hoses near intake runner #4. To do this spray carb cleaner at parting line between manifold and block while engine is running. If leaking rpm will dramatically change. A leak will lean out that cyl and cause misfire