What the hell is happing here.

[Acewolff]

Okay. New owner of an 04 liberty. Car sat for 3 years.

I buy the car, runs good, a rad hose leaks and it needs injector 6. Was throwing a code for open circuit.
But I will note. If you let it sit over night, It would run completely normal the next day. Until you shut it off. Didn’t matter if it was 30 seconds or 4 hours. It would run great. Then once you shut it off and restarted it would misfire like mad.
Got injector, changed. All the others were operating normal so I just changed the seals and called it good.
Now it runs like absolute garbage. Takes forever to start, stumbles and shakes, shifts hard out of first, stalls sometimes, misfires heavy when your on the throttle.

Throwing strange codes also, like missing vin, driver position undetermined, one for the map, which I changed right before making this post, and one for the crank position sensor.

I’ve been wrestling with this for 5 days now and don’t know what to do next. Obviously the crank sensor but I don’t feel like that will fix anything.

Any thoughts?

 

[KJowner]

I'd guess bad battery, they are old school and have a high voltage bus that's easy corrupted if the voltage dips on startup.

 

[WheelNut]

Symptoms sound like a bad fuel pump to me because those problems are all related to the engine wanting more fuel and not getting enough. Check the fuel pressure with a gauge and see how it looks (I don't know the spec off the top of my head, but it shouldn't be hard to find online). Download the factory service manual for the KJ- it is a lifesaver.
The battery is definitely also a suspect like KJowner said. Weird electronics codes appearing randomly fit with a bad battery as various modules won't get the adequate voltage they require and will show error codes. If the Jeep has been sitting for 3 years I'd bet it needs a battery by now anyhow, since it was likely damaged by sitting fully discharged for an extended period of time. Unless you KNOW that battery is good in my experience it's always good practice to put in a fresh battery to avoid issues when winter hits. Nearly every used car I've bought has needed a fresh battery. My KJ being one of the few exceptions, but lucky for me it had a 2020 date engraved on the battery when I bought it.

 

[Johnny O]

I'd guess bad battery, they are old school and have a high voltage bus that's easy corrupted if the voltage dips on startup.

I agree. Liberty Electronic Gremlin Hunting should always start with the battery.

 

[Acewolff]

So I auctually narrowed it down to the code readers I was using. Apparently the computer in these is some type of hybrid and the readers I was using were cheep.
I have went to my buddy’s shop and used his snap on reader and it tells me the crankshaft sensor and the iac are bad.
Fast forward to now, I’m sitting in a parking lot, changing my crank sensor. And the broken end falls into the bell housing.