2003 jeep liberty

[Rangermeyer275]

So the problem I am having is it throws a code on spark plugs and cils.
It will run great then all of a sudden I can barely keep it running. I will have to pull the negative battery cable and that seems to reset it. The only code is plugs.
Any help would be appreciated

 

[tommudd]

What spark plugs are you running and how long have they been in there ?
NGK coppers only and every 30-35000 miles

 

[Rangermeyer275]

I will change those tomorrow

 

[WyldWolf777]

I will change those tomorrow

I threw a set of NGK copper in mine and huge difference!

 

[Rangermeyer275]

Threw in new ngk plugs. Now I get an evap leak once in a while that just lags the motor and miss fires it. Gas cap good. I will rest it and it will be fine for 150 miles. Then throws a leak code. Only happens when I start it once in a while. Any ideas

 

[Rangermeyer275]

Threw in new ngk plugs. Now I get an evap leak once in a while that just lags the motor and miss fires it. Gas cap good. I will rest it and it will be fine for 150 miles. Then throws a leak code. Only happens when I start it once in a while. Any ideas

I will reset code

 

[tommudd]

Threw in new ngk plugs. Now I get an evap leak once in a while that just lags the motor and miss fires it. Gas cap good. I will rest it and it will be fine for 150 miles. Then throws a leak code. Only happens when I start it once in a while. Any ideas

Need to go over all hoses and check them very close, there can be a very small crack in one of the hoses that maybe hard to see
Common issues as these KJs get older , hoses do not last forever

 

[Rough]

Threw in new ngk plugs. Now I get an evap leak once in a while that just lags the motor and miss fires it. Gas cap good. I will rest it and it will be fine for 150 miles. Then throws a leak code. Only happens when I start it once in a while. Any ideas

The CEL may not activate until the fault is detected several times over multiple start ups. Once you erase the code you're restarting the process. Initially thought mine was the gas cap but found it was a very small leak in the vapor leak detection pump, just enough to set the code about once a week. Later found that a leaking gas cap will set a dash warning light of it's own.

 

[Rangermeyer275]

Ty

 

[Ksat]

Threw in new ngk plugs. Now I get an evap leak once in a while that just lags the motor and miss fires it. Gas cap good. I will rest it and it will be fine for 150 miles. Then throws a leak code. Only happens when I start it once in a while. Any ideas

Are you sure the EVAP issue is what's causing the lagging and misfiring? You mentioned earlier you were getting codes for "spark plugs and coils," but what were those codes exactly?

An EVAP problem could cause a vacuum leak which can make the engine run as you described, but I don't know if you can just assume that because you have a related code.

 

[Rangermeyer275]

The CEL may not activate until the fault is detected several times over multiple start ups. Once you erase the code you're restarting the process. Initially thought mine was the gas cap but found it was a very small leak in the vapor leak detection pump, just enough to set the code about once a week. Later found that a leaking gas cap will set a dash warning light of it's own.

i will have to check it this weekend as i work a lot of hours. ty