2011 jeep liberty 6 cyl no 5 coil might need replacing

jeep liberty 6 cyl ode 5 misfire pops up then engine light goes out jeep runs OK sometimes at 60 MPH mises then goes back to good again ,. is it the coil plug or fuel injector

This could be the just a spark plug.
When did you last get the plugs changed?

And get the codes read

It could be a coil problem, or the wiring to the coil, or an injector problem…

I would first replace the plugs.



Before you do anything else, I would perform a compression test

Call me a pessimist if you like, but I think you should make sure the engine is okay mechanically before throwing a bunch of money at the vehicle

If you’ve already got a compression gauge, using it will cost you nothing

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A compression test is a great idea in this case. For one thing, it means you take out all the spark plugs, and inspecting them may give some important clues even before doing the compression test.

THANK you however that would take a lot of work and removing to top half of the plumbing around those coils. , just one cylinder is missing ,one code for it .

Or the spark plug, or a sticky valve, or a broken wire, or a …

Like Yosemite asked, what are the codes?

So you got a p0303 diagnostic code? Common causes for that to check for are (from more likely to less likely)

  • faulty spark plug
  • faulty coil or wiring from ignition module to coil
  • faulty injector or wiring from ecm to injector
  • low compression
  • faulty crank position sensor

Check the fuel trims too. Easy to do & could provide a clue to what’s happening. A common method to diagnosing single cylinder misfires is swapping stuff around. If you swap the coils and the problem move also, you know it’s probably the coil.

switch that “bad” coil with another one and see if the problems follows. If yes, you have a bad coil. If not then you might as well follow all the other suggestions mentioned here.

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