2004 Jeep Grand Cherokee running rough with code P0122. Previously had codes p0300, P0302, and P0303. I replaced the spark plugs and those 3 codes went away. Now the P0122 came on and the engine runs a little rough when idling in gear. It runs fine when driving but when stopping at a light it rouns unevenly. 2010 Dodge Grand Caravan 4.0 v6 OBDii Codes p0300 and p0152 got 2 codes for P0300 mult. misfire and P0152 for O2 sensor bank 2 sensor 1 high voltage. i am gearing more towards the O2 sensor which send the wrong fuel signal to injectors and i get the mis fire code. but then again sometimes the misfire sends the wrong info to the exhaust and 2014 JKR Granite Crystal, 5.13 Auto: RK X Factor 2.5 Inch Lift, Artec Front and Rear Truss, Artec Rear LCA Mounts/Skids, Poison Spyder HD Crossmember, Rock Hard Gas/TC/Evap/Oil Skids, Rough Country Diff Sliders, Nitto Trail Grapplers 37x12.5x17, Pro Comp 97 Series Wheels, Synergy Weld On Rear Trackbar Bracket, PSC Hydroassist, T6 Aluminum Tie Rod, G2 Gold Chromoly Axle Shaft/RCV front axle 97 jeep grand cherokee laredo 4.0L cannot get rid of the p0201, p0202, p0203; p0204, p0205, and p0206 codes We have done so much, I can write a book. Let's start briefly from the beginning. We blew motor. Purchased one from junkyard. it sat for almost 2 yrs before the project was started. Diagnosing cylinder misfire usually comes with the code P0300 On a Jeep Liberty 2002 - 2008! This is the MOST COMMON CAUSE for the 3.7 L V6 ! Also itā€™s very 385 posts Ā· Joined 2012. #1 Ā· May 4, 2014. So I've been chasing an Evap code, P0455, for a year now. 03 4.7. Smoke checked it four times, replaced the leak detection pump, several hoses and two new gas caps. Finally seems to be fixed, wanted to share my solution: The PCV hoses! Hidden behind the valve covers is the PCV crossover, all three Hello, working on a 2012 Jeep Grand Cherokee with a 3.6. A few weeks ago got code P0300. The car has about 80K on it so I replaced the spark plugs. Ran fine for about 3 weeks then staring running rough and P0300 came back. Canā€™t see any vacuum leaks but Iā€™ll run a smoke test to confirm. The P0305 trouble code will trigger the Grand Cherokeeā€™s service engine soon light. The vehicle itself may begin to run rough. It depends on how serious the misfire is. The vehicle may produce excess vibration, especially at lower RPM. Fuel mileage may suffer. You may smell raw gas coming from the tailpipe. The codes and their respective definitions are below. P0300 - Random/Multiple Cylinder Misfire Detected. P0305 - Cylinder #5 Misfire Detected. P0351 - Ignition Coil A Primary/Secondary Circuit Malfunction. P0306 - Cylinder #6 Misfire Detected. Posted on Aug 29, 2010. 2000 Jeep Grand Cherokee codes p0132 p0141 p0152 p0161 Keep Coming Back. The code P0300 is a random misfire code. This does not mean change the spark plugs. This R1iEnX5.