2009 Mercury Mariner P0302 Cylinder #2 Misfire---NEED HELP!

Novice1933Novice1933 Member Posts: 4
edited November 2018 in Mercury
2009 Mercury Mariner, 2.5L 4cy, fw drive, 180K miles, replaced tranny 2 years ago with a used one that now has about 90K miles on it. I have been getting a P0302 error, signifying a misfire in cylinder #2. When I put the vehicle in drive, with the break down, it slightly vibrates, but when I pick up speed at around 45-60mph, it vibrates at a much more intensive rate. I have replaced all of the plugs, changed out the coil packs, and replaced the valve cover gasket. Still no change in the vibration. Did compression tests on all 4 cylinders, and they all came back at 120. I have been told that it could possibly be the torque converter, but are there ANY other items that could be causing the P0302 error? I don't want to get into changing out the TC, if there are other items I can check first; or, is there a way to determine exactly if it is the TC? Any help is greatly appreciated!!!


  • PF_FlyerPF_Flyer Member Posts: 9,372
    Replace wires? Possible fuel injector? Fuel pressure?

    I'm no expert, but I'm curious how the torque converter would have anything to do with a misfire. You certainly could get a vibration from a TC problem, but connecting that to a code for a misfire seems odd.
  • TheGrinchTheGrinch Member Posts: 1
    Novice1933 - were you ever able to diagnose the problem? Having the exact same problem with my 09 Mariner at 175k
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