2002 Jeep Liberty 3.7L running really lean?

[2008SRT4]

Hi Guys/Girls,

I just replaced the spark plugs in my girl friends 2002 jeep liberty 3.7L Auto. When I pulled the old plugs I was surprised to see that they were white as could be (lean) and ate away to about .070 thousands. Factory specs are .040 thousands so they were pretty ate up telling me that she might be getting some detonation due to the lean conditions. The car has about 67000 on it and she bought it off some guy so idk if they were ever done at 30k like they were supposed to be. Anyways I put NGK iridium's in it so she wouldn't have to worry about them again and replaced the external fuel filter, let her put a few miles on it and pulled them out again to check them. There white like the old plugs (lean) and it is now throwing a P0161 Code which is O2 sensor heater circuit malfunction, Bank 2 sensor 2, so right side after the cat. I guess I am just going to change that sensor and hope that is why its running lean. I also added some Lucus fuel injector cleaner to the fuel tank so we will see what that does. Anyone else got any other ideas why it could be running lean?

I'm worried if its detonating with the iridium plugs that the plugs wont be the first thing ate up. More like a hole through the piston!

Any input is appreciated!

Thanks in advance, Tom

 

[ThunderbirdJunkie]

How many miles were on the KJ when you replaced them? Is she running regular gas? ThunderbirdJunkie's '02 3.7 DOES NOT like anything less than 89. It WILL ping on 87, and has been like that ever since 50k miles.

Tell her to keep 89 in it, and not to BAWWWW over the extra $2/tank that it costs, and look at the plugs again in a couple thousand miles.

 

[twack]

does a kj pull timeing or anything with detenation?

 

[ThunderbirdJunkie]

Yeah, but pulling timing only lessens it, it doesn't get rid of it completely.

 

[twack]

Yeah, but pulling timing only lessens it, it doesn't get rid of it completely.

i was just curious what failsafes the 3.7 have.

 

[ThunderbirdJunkie]

Detonation is preignition, which means the engine is firing before spark is in the picture, so it doesn't matter how much timing it pulls.

 

[2003renegade]

TBJ. i like Quote:
This section removed because it hurt somebody's feelings


funnies

 

[2008SRT4]

How many miles were on the KJ when you replaced them? Is she running regular gas? ThunderbirdJunkie's '02 3.7 DOES NOT like anything less than 89. It WILL ping on 87, and has been like that ever since 50k miles.

Tell her to keep 89 in it, and not to BAWWWW over the extra $2/tank that it costs, and look at the plugs again in a couple thousand miles.

I replaced the O2 sensor that is was calling for and told her to run the 89 octane like you said for about a week or so and I will check the plugs again. Thanks for the help!

 

[ThunderbirdJunkie]

No problem!

 

[Lashlarue]

Partially plugged injectors will cause it to run lean.My prior vehicle was a C5 Vette and I had similar troubles.Tried Seafoam, Techron and Berryman B-12. The Berryman was least expensive and worked like magic.Corvettes have dual fuel tanks and a balance tube, and before I got a lean code, the gas guage would quit working.I put a can in my Liberty about every 2000 miles.Have had no problems whatsoever and with my mild modes get 19 in town and 25+ on the road.My mods are a K&N and a Magnaflow catback.Mine runs rich when I have too many trips to wallyworld, it's only 2 miles one way.

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