2002 liberty flashing cel and missfire

[Jeepjiberty]

Ok so bought this 02 liberty the other day and It had some issues lol. Engine light was on solid for a cylinder4 miss. The code said to change the fuel injector, so I did that. Still missing so I decided to change the coil.. and after I changed the coil it switched up from a cylinder 4 miss to a cylinder 3 miss. And now the cel is flashing. The scanner said bad coil. So I'm a little puzzled as to why the missfire moved. Only thing I haven't done was change plugs. So should I change those first on all cylinder or buy the coil and see if it moves again?

 

[tommudd]

Throw a new set of NGK copper plugs in, check over the coils real close
and see how it reacts
I assume it is a 3.7

 

[Jeepjiberty]

Throw a new set of NGK copper plugs in, check over the coils real close
and see how it reacts
I assume it is a 3.7

Yes sorry it's a 3.7 I have a set of champion plugs for it now should I take them back and get ngk then

 

[LibertyTC]

Use the correct NGK factory plugs.
Hopefully that may help.

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[Jeepjiberty]

Use the correct NGK factory plugs.
Hopefully that may help.

You must be registered for see images attach

Awesome I'll try that

 

[A. Sandoval]

Ok so bought this 02 liberty the other day and It had some issues lol. Engine light was on solid for a cylinder4 miss. The code said to change the fuel injector, so I did that. Still missing so I decided to change the coil.. and after I changed the coil it switched up from a cylinder 4 miss to a cylinder 3 miss. And now the cel is flashing. The scanner said bad coil. So I'm a little puzzled as to why the missfire moved. Only thing I haven't done was change plugs. So should I change those first on all cylinder or buy the coil and see if it moves again?

I had a similar problem. After changing plugs, the fault moved cylinders, I somehow realized the plugs were good but arcing up the ceramic body, The solution was to put dielectric on the ceramic to stop the arcing. Haven't had a problem since.

 

[gayle.woods]

Awesome I'll try that

The scan tool can’t really tell if the coil is good or bad. It only know that something is not right and points you in that direction. A lab scope and ohm meter can tell you more but a coil can test good but break down under load after it gets hot.
Another good way to test for a bad coil is to switch it with another coil and see if the miss follows the coil.

 

[WyldWolf777]

Throw a new set of NGK copper plugs in, check over the coils real close
and see how it reacts
I assume it is a 3.7

I did this and it worked solved the misfire!