03 Jeep Liberty random misfire

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

just check online: P0300 Jeep; and the10 possibilities will be given you.

po300 is random miss fire doubtful two O2 sensors bad at one time most likely coolant temp sensor is bad causing engine to run rich this will cause O2 sensors to throw a code(thats what they are there for..exhaust gas temp. and raw fuel) running rich will also fowl spark plugs(=miss fire) P1128 ??

po300 is Random/Multiple Cylinder Misfire Detected.This means the PCM sees misfires on more than one cylinder,so it's probably a fuel issue.You might have a bad fuel pump(bearings are binding,causing low fuel volume).It could be the in-tank filter is plugged up,or maybe the in-line filter.Start with the easiest-the in-line filter.

random misfires are from spark plugs --HT leads--injector/s--ignition coil/s---low compression---wiring
have a fuel pressure test done to check for pump, filter and pressure regulator problems
use a quality injector cleaner for a tank full
check for vacuum leaks ( vent controls hoses , transmission actuator , brake booster when the foot is on the brakes

Check injector pulse to make sure the computer is commanding the injector on and off. Check that the plug isn't cracked. Check cylinder compression if all ok you may need and injector but you could probably try an injector cleaning service( not the stuff you throw in the tank)

misfires are more from problem injectors, low fuel pressure or injector wiring than from plugs
have a fuel pressure test done to check for problem pressure regulator , problem fuel pump , blocked m/dirty filter
one other area of concern is the EVAP system where the purge valve doesn't vent the tank properly and causes low fuel flow rates

Check the camshaft position sensor. They are notorious for causing these symptoms.

check coil and plug wire. If both test good have compression test done on that cylinder

Replace the coil pack.