Multiple Misfire 2003 Jeep Liberty Sport 3.7L

[LibertySport]

Good Morning,

Jeep is showing multiple misfires and bogged on me this morning.

The thing is though I've replaced the spark plugs with NGKs and also replaced the ignition coils 1 and 3. The only reason 1 and 3 were replaced because the spring was jacked inside the coil. All the other coils checked out.

Plugged in the OBDII scanner this morning and got P0300 (Multiple Misfire), P0303(Cylinder Misfire 3), P0305 (Cylinder Misfire 5), and P0306 (Cylinder Misfire 6).
*Cylinder 5 just came up this morning.

I re-seated Cylinder ignition coil 3 and it went off for a while and ever since 6 started misfiring it started spreading like a wild fire.

I checked the ignition coil over cylinder 6 and it is fine and so is the spark plug. I'm going to reseat the spark plug once I get home.

Any other suggestions would much appreciated.

Just for clarification the Jeep is a 2003 Jeep Liberty 3.7L Sport.

As far as I understand the diagram for the cylinders goes (looking from the front of the Jeep):

1 4
2 5
3 6

If this isn't correct please let me know.

 

[uss2defiant]

No, that's not correct which explains why your problem isn't fixed.

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[CalcityRenegade]

uss2 is correct with the cylinders, How do you know the coil packs are still good? Just curious.

 

[uss2defiant]

uss2 is correct with the cylinders, How do you know the coil packs are still good? Just curious.

you can check the resistance of the coils.
primary resistance between 0.6-0.9 ohms
secondary resistance at 6k to 9k ohms

if i remember correctly primary is between the connector pins and the other is from one of the pins to the internal spring.
you want to also make sure that there is no building with the plastic cylinder housing. two of my coils had bulges.

 

[CalcityRenegade]

you can check the resistance of the coils.
primary resistance between 0.6-0.9 ohms
secondary resistance at 6k to 9k ohms

if i remember correctly primary is between the connector pins and the other is from one of the pins to the internal spring.
you want to also make sure that there is no building with the plastic cylinder housing. two of my coils had bulges.

Thanks for the info, I should have been more specific lol, I knew they could be tested but I was curious if OP had them tested as he said he knew they were good, I thought he might have just given them a visual inspection.

 

[LibertySport]

Awesome, I had a feeling I was wrong. I'll re test my coils this weekend just to be sure and eliminate this issue.

Thanks uss2. Appreciate the help!

 

[CarabouSpider]

Hi LibertySport,

Did you manage to get this issue resolved? I am facing similar symptoms on my ‘02 3.7 Liberty.

Thanks!