An engine misfire at idle (rough idle), accompanied by illumination or flashing of the Check Engine Light, could indicate a problem with one or more of the intake valves. Revised intake valves & valve locks are available to address this concern.Google+
Car Problem Reports
Jeep Liberty Check Engine Light/Misfire Due to Intake Valve Locks/Valves
Jeep Liberty Problem
Engines Affected: 2.4L 4 Cylinder, 2.8L Diesel, 3.7L V6
Average Mileage: 97,898 mi (12,100 mi - 220,000 mi)
Jeep suddenly would not start unless you aggressively apply the accelerator and maintain above 1500 RPM, it would not idle, and reported a P0306 diagnostic code (Cylinder 6 misfire). FYI the last digit is the cylinder # so you may see a different P030X. I replace the spark plugs and Ignition coils when first trying to diagnose this problem, until I found this website and people described the Intake valve problem. Borrowed a compression tester from a friend and found NO COMPRESSION on cylinder 6!!
If you are experiencing a similar problem save yourself $150 and do a compression test!
Like this comment if I saved you a buck!
Visitor, 2002 Jeep Liberty, 3.7L V6
At around 90,000 miles my engine light went on and began flashing and the engine would roughly idle. If I turn the engine on and off, it becomes driveable. I took it to the mechanic and he said it was my #2 cyl and that coolant was leaking into the cylinder. ...about a 2,0000.00 job for a both heads, gasket, labor, machining, etc. He told me that this problem, along with the transmission (clunking in rearend) is "common". When I spoke to a Jeep rep online, I was told that their only recall was for the airbag deployment; I find that interesting because I am not the only one to have this cyl problem. Jeep needs to recognize this "common" problem.
Visitor, 2006 Jeep Liberty, 2.8L Diesel, 73,000 mi
MY 2006 JEEP LIBERTY HAD ALL THE CLASSIC "RANDOM MISSFIRE" TROUBLE CODES. iTOOK IT TO THE JEEP DEALER AND THEY TOLD ME THE STANDARD TSB STORY ABOUT INTAKE VALVES AND RECOMMENDED A VALVE JOB AT AN EXSTIMATED COST OF $2800. I ELECTED TO DO THE VALVE JOB MYSELF, WITH A PROFESSIONAL MACHINE SHOP PERFORMING THE MACHINE WORK. I PURCHASED ALL NEW INTAKE VALVES AND KEEPERS FROM JEEP AND PUT IT ALL BACK TOGETHER AND I STILL HAD THE THE EXACT SAME MISSFIRE. AFTER SOME FURTHER RESEARCH I DECIDED THAT THE PROBLEM APPEARED TO BE A PROBLEM WITH THE OXYGEN SENSORS, BECAUSE THE OXYGEN SENSORS DID NOT BECOME ACTIVE UNTIL THEY REACHED 600 DEGREES, WHICH SEEMED TO CORRESPOND WITH THE MISS DISSAPEARING AFTER ABOUT 30-60 SECONDS AFTER STARTUP. I REPLACED BOTH PRIMARY O2 SENSORS, AND THE MISS IS GONE. I RECOMMEND THAT ANYONE WHO HAS THIS PROBLEM PERFORM A COMPRESSION TEST, AND IF ALL CYLINDERS ARE OK, THEN REPLACE THE O2 SENSORS. GOOD LUCK, AND DON'T BELEIVE ALL THE EXPERTS THAT ARE IN A POSITION TO PROFIT FROM YOUR PROBLEM.
Visitor, 2002 Jeep Liberty, 3.7L V6, 128,000 mi
After flushing the radiator, my 2002 jeep liberty engine light came on. misfire. cyl 2,3 and 6. my o2 sensor is bad too. i change all spark plugs and ignition coil for cyl 6. nothing seems to work. When i start the car the engine light starts to flash and engine knocks. help please!
Misfire cyc 4 and random cyc misfires, changed coil packs and plugs... sounds as if rod going to come through engine... I now have a payment and no car to drive... when is jeep going to be held responsible for numerous reports of this with their 3.7L engines...
Visitor, 2002 Jeep Liberty, 3.7L V6, 129,800 mi
I've changed the apark plugs, the coils, had the unjectors flushed and my check engine light remains on and blinks occasionally.
The OBD codes indicate misfiring issues with the 2nd, 4th, and 6th cylinders, but I'm leaning towards an issue with the intale valves!
The most frustrating part of this is the fact that I've taken it to the dealership three times in the past three months and they have yet to fix the problem, but they still charge me an arm and a leg for their so-called "repairs"!
I've never had any problems with my Liberty until recently, so we're taking it in to a local repair shop this afternoon. I'll provide an update as soon as I know what the REAL problem is!
Visitor, 2005 Jeep Liberty, 3.7L V6, 28,000 mi
Check engine light came on (misfire on cylinder 4) - spark plugs replaced. Light came on again (misfire on cylinder 4) - switched coil from 4 to 2. Light came on again (misfire on cylinder 4) - found out today that every valve on the right side of the engine is burnt. The story from the mechanic it is that due to some carbon build up and it has caused the valve guides to go bad. He also stated that not driving it enough can be a cause for the carbon build up. He also found that one of the timing chain guides had broken . . on the right side. Coincidence? So, $3100 later it is time to say goodbye to the Liberty
Vehicle stalled, would start but die at idle. towed to Repair shop where found #5 intake valve keeper missing, broken valve spring and damaged valve. Valve guidein the head was cracked(no longer able to get a replacement guide from Jeep). Had to replace left cylinder head and valves. Replaced intake valves and valve locks on right cylinder head (a kit sold by Jeep to fix this problem)as per Jeep Service Bulletin TSB 09-007-06. Although we had this vehicle in to Chrysler on more than one occasion both for engine light illumination and rough idle, no one ever alerted us to this service bulletin and the fact that there was a kit to prevent the resulting $2300.00 repair.
Found zero compression on cylinder #6 after finding the 0306 code. So far no solution
I purchased a 2005 Jeep Liberty Sport on 12/9/10. Within 100 miles after driving it off the dealer's lot, the check engine light came on. The dealer has had it in for repairs on 4 different occasions for a total of 37 days in three different repair shops. I have only owned the vehicle 71 days and it's spent 37 days in repair shops! They have put in 6 new spark plugs, a new serpentine belt tensioner, performed a two part valve and induction system cleaning, installed a new water pump and finally did a valve job on it. They just completed installation of 12 new valves and keepers. Thankfully all this work was performed under warranty. I'm picking my Jeep up from the dealership today (after 26 days in the repair shop) and I'm praying that the check engine light stays OFF!!!