Engine doesn't idea?

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

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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

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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

Based upon the symptom described, my best guess would be a faulty crankshaft position sensor.

The engine does not have a distributor. There are 3 coils for 6 cylinders.
You can switch coils with another cylinder and see if the problem moves.
You can also check the plug for spark.
Generally speaking, oil on the inside of a plug is caused by internal cylinder problems.

have you cleared the codes between fault reads
clean the maf first .....replace the maf if faulty
coil packs ?
injectors

get a compression test done on the engine, something may be fouling out the spark plug causing the misfire to occur.

Hi Jason:
A Random/Multiple Cylinder Misfire Detected unfortunately doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.

A code Random/Multiple Cylinder Misfire Detected 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

Possible Solutions:
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
I know the elm327 plastic 1.4 can help you reset the code....
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Hi. This vehicle is equipped with a Electronic distributor ignition assembly. There is no ICM(ignition control module) on your model. This will narrow the problem areas down a bit. The most common area of concern will be the distributor cap.This Component may be worn, cracked, or loose. Inspect the cap for faults, and replace if necessary. The next area of concern will be a set of faulty, or worn spark plug wires. Inspect the wire sets for damage. If you have not replaced the sets for quite some time, simply replace them asap.

Another area of concern will be the coils. The ignition coil is designed to operate without an external ballast resistor. Inspect the coil for arcing. Test the coil primary and secondary resistance. When using an ohmmeter, the primary readings should be 0.97-1.18 ohms and the secondary resistance should be 11,300-15,300 ohms. replace the coil(s), that do not rate correctly.

The above areas are the most common. Here is a list of some other problem areas, that will cause multiple misfiring.

1. Crankshaft/Camshaft sensor- Check the wiring at the Crankshaft sensor housing. Make sure the sensor is not loose, or damaged. The cam sensor is mounted in the distributor rotor area, under the cap. It is an integrated part of the distributor.

2. Spark plug(s)- replace if necessary.

3. PCV Valve - Check the valve, and hose for damage.

4. Fuel Pump - A weak fuel pump will produce less than normal pressure. this will cause the engine g to misfire. Check the ground at the pump for corrosion. Clean, ro replace, if necessary.

5. Timing settings - A slipped timing chain, or belt will cause a misfire, also. check the timing ratings for slipped intervals. replace the belt, or chain, if needed.

6. Injectors - A faulty set of injectors will cause a misfire. make sure that the injectors are functioning properly.

7. MAP- A failed MAP sensor will induce misfiring. This will, usually, will trigger the engine light.

this is more common on high mileage cars. you should probably replace all the coils as it's common for them to go bad on this model car

Connect a voltmeter set on ac volts to the pickup coil wires (disconnected from the module) and crank the engine.

2. The pick-up coil output should be more than 0.7v AC. If not, replace the pick up coil and distributor shaft.

3. Visually inspect the condition of the magnet on top of the distributor shaft to be in good condition. If not, replace the distributor

1. Disconnect the set timing connector or ground the Tan/Black bypass wire.

2. The check engine light should come on and code 42 should set.

3. If the engine stops stalling, disconnect the pick up coil connector at the Ignition Control Module (ICM).

4. Check acv output from the pick up coil while cranking the engine at a normal cranking speed.

5. If output is less than 700 mv replace the distributor shaft with a new one.