Recently bought an 02 KJ. Suddenly, the lights go off.

[KJV]

Hello ya'll,

As far as I can see, this is the best place to get info for the Jeep Liberty. So, if you guys don't mind, I'd like to get your input on a problem I am having. I bought an 02 Liberty Limited with the v6 4wd.

I am the second owner, and the first owner seemed to be very particular about how everything of his was kept (he was a lawyer who only used this jeep to go skiing or kayaking. His wife made him get ride of one of his cars. He kept the m3 and miata and bought himself a new Cherokee instead). The car in general seems to be in pretty good condition. I am fairly mechanical, I've rebuilt an engine before and do most all my own work on anything I own.

I am getting p0171, p0174, p0306 and p0442. All 4 of these one random day all at the same time after several short trips in a row I checked under the hood and found two cracked pipes and switched those out, rset the computer and still the same. A few times when the tempeture outside was in transition, on cold mornings the lights would go out, so that leads me to believe that the vehicle is running heavy, not lean like the codes suggest.

As I go under the hood and start tracing all rubber, do you guys have any other suggestions? I have searched for a few hours online (I don't feel like crawling under the jeep in 20 degree tempature) and couldn't find someone else getting all four codes at once.

From what I see I should also check MAF, Idle control valve, crankcase vent valve and pre-02 sensor (anyone just happen to know the location?) Anything else besides fuelcap come to mind? Thanks.

 

[tommudd]

First two are the O2 sensors on the left side of the engine ( drivers side)
1/1 and 1/2
The second one could be caused by the first O2 ( 1/1) sensor being bad or could be another issue
1/1 could be any of the following
The MAF Sensor is dirty or faulty Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There could be a vacuum leak downstream of the MAF sensor Possible cracked vacuum or PCV line/connection Faulty or stuck open PCV valve Failed or faulty oxygen sensor ( 1/1) Sticking/plugged or failed fuel injector Low fuel pressure (possible plugged/dirty fuel filter!) Exhaust leak between engine and first oxygen sensor
1/2 is more of the same but again could be caused by 1/1
P0306 is number 6 not firing or issues with it ( last cylinder on the right side ( passenger)
Po442 is one of the following or start with these
Missing or loose fuel cap
EVAP canister, or system hose leak, gas tank leaking
so check gas cap, check lines around the EVAP canister as a start

 

[LibertyTC]

Welcome to the forums Dave!
Tom has done the list very well for you.
How is the jeep running over all?
I would pull the # 6 spark plug (Or all of them) and hopefully you will find a champion or NGK copper core plug in there correctly gapped, that is not burned away.
On the under the hood sticker is the correct NGK plug listed with gap.
Members often replace their plugs at 30k miles is best.
The Jeep may not like others. What spark plugs are currently in there?
You are going to have to get under the jeep to inspect the EVAP lines just ahead & around the fuel tank. This is often where leaks are found as well.
Up on the lift is best, and having a shop with a smoke machine, can find leaks quickly.
Trying a new Mopar gas cap may be best as well.
How many miles are on this Jeep?
The PCV is located on the oil filler tube/neck and can crack the plastic neck easily if not removed properly. I would replace the PCV anyways, not an expensive part. If it is cold out, I heat the hose with a hairdryer, then gently remove the hose going into the PCV, and then warm pcv, and twist it counter clock wise to remove it.
Warmed plastic does not go snap, like when it is cold.

 

[KJV]

hey, sorry for the delay. I got locked out of the Forum and really didn't have a day off after the holidays until today (Snow day!) .

So, I went around tightening stuff up, and then reset the battery, and nothing since. Weird huh?

But yet on my way home the other day, I had a more-sudden break (guy decided to get over a lane and stop for the red light in front of me. Not a lock up, just a harder.) and my oil-light came on, but as soon as I went off the break, the oil light went off. Anyone ever have that happen (Oil was a little low, I know I am burning).

 

[CactusJacked]

But yet on my way home the other day, I had a more-sudden break (guy decided to get over a lane and stop for the red light in front of me. Not a lock up, just a harder.) and my oil-light came on, but as soon as I went off the break, the oil light went off. Anyone ever have that happen (Oil was a little low, I know I am burning).

Your oil being low is why. When the engine is running, oil is disbursed throughout the engine, and not as much is in the pan as when the engine isn't running. When you slammed on the brakes, what little oil that was left in the pan sloshed forward, the oil pump sucked air, and you were momentarily without oil. No oil pressure=oil light on, plus that's bad for the engine. Keep a close watchful eye on the oil level, especially since you know your engine burns it.