2002 jeep liberty misfire

[rfbrenn]

2002 LIBERTY 3.7L. My Liberty has 90,000 miles and in the mornings it often runs rough and CEL light blinks. It codes up to be a # 6 misfire. I have replaced the plugs and # 6 coil and it still does it.If I turn it off and then immediately restart it is fine.I have seen on the net that there seems to be alot of people with the same problem but I have not found an answer, I do not think it is valves or anything like that, it seems to be electrical but I do not want to start just replacing parts unless that part is the problem

 

[SteelHeadz]

The next step is to do a compression test.

 

[Jester32]

Compression test. Check make sure plug isn't fouling. Make sure your injector and coil is firing. Ive seen many broken plugs on # 6 from install I use a normal socket as a spark plug socket with the rubber will often stress the plug so it cracks.

 

[54cj3b]

Could be a valve starting to unseat itself , I had same kind of symptom about a year ago with a miss in a 06 liberty

 

[Jester32]

They also like to spit out cam followers that's will cause a miss.

 

[Maginus]

Wonder if anybody has an answer to the random misfiring...I have the same problem, changed the coil, spark plug, checked compression, fuel pump...etc...mine is a 2003 with 170,000 mileage on it....
One mechanic suspect it's the cylinder heads (cracked), another did not think so...due to its random nature....(the shaking will stop when restart the car)
Don't know how much it is going to cost me to change this and that to see if it helps the issue....the cylinder heads will cost a couple of grand at least...so if it comes to that, I think I have to say goodbye to my beloved jeep....

Just wonder if I can keep driving it and how long it will last.....anybody knows what could happen if I ignore the problem??

Well, if someone knows how to fix it, that will be much better and much appreciated....

Thanks

 

[SteelHeadz]

John has a good pointer for the 3.7 liter on the misfire issue. The valves could be getting partially stuck open and due to heavy deposits on the valves and valve seats. Also, the valve springs and keepers along with the rocker arms needs to be checked.

 

[Maginus]

John has a good pointer for the 3.7 liter on the misfire issue. The valves could be getting partially stuck open and due to heavy deposits on the valves and valve seats. Also, the valve springs and keepers along with the rocker arms needs to be checked.

Thanks, will get the checked.....