Weird engine behavior rain related?

[Joey D]

I bought this 2006 KJ last fall, didn't start driving it until December. I'm in Minnesota so I drove it all winter with the only issue being it didn't want to start after being driven and thoroughly warmed up between 10 and 30 minutes after shutting it off.
I replaced plugs, coil packs, PCV, crank and camshaft sensors which didn't change anything. Well plugs were really bad, that seemed to help.
Now springtime, we had a good rain and engine light came on, I checked for codes and got 3. P0562 PCM voltage low, P0700 transmission control malf., P0420 Cat Conv O2 sensor. Seemed to run fine anyway and light went off in a couple days.
Last week started to get a weird vibration 25-30 mph but not while accelerating, like the tires were bad or something. Tires are new. Google searches made me think rear U joints so I bought them and was going to change today.
Yesterday we had another good rain and I drove maybe 25 miles, vibrations now went away.

Not sure what to think. A related subject I bought a used PCM ebay they asked for existing PCM p/n, VIN, and mileage to program it? I was going to try it to see if it fixed the original starting issue but haven't tried it yet.

Now I don't know what to think.
Hoping someone had some experience or insight into possible causes.

 

[LibertyTC]

How many miles on the KJ now? I assume it would turn over & not want to fire ..?
Weird vibration, could you tell if it was from front or rear?
Did you use NGK plugs ZFR6F-11G-Gap at .040 inch ?
Would recommend a fuel pressure test. What is the fuel psi readings? Key on psi, running psi, key off for 20 min psi?
PCM voltage low, check battery cables clean & tight, running voltage at battery is?
Need to get a new NTK 02 sensor by the sounds of it-420.
Trans 0700 oh, have you serviced the trans fluid & filter?
Bill our electrical specialist will follow this post I've never swapped out the PCM, Bill can help on that one.

 

[Billwill]

The sellers of the PCM are doing the right thing I believe!
They want to know you will be getting the correct Part and want to program the VIN and Mileage into it as is required by Law in most Countries.

Hopefully knowing the VIN they will also have programed the SKEES code into it otherwise the PCM will not recognize the Coded Keys!

If you have the PCM in your possession it is worth installing it to see if it works!

 

[Joey D]

How many miles on the KJ now? I assume it would turn over & not want to fire ..?
Weird vibration, could you tell if it was from front or rear?
Did you use NGK plugs ZFR6F-11G-Gap at .040 inch ?
Would recommend a fuel pressure test. What is the fuel psi readings? Key on psi, running psi, key off for 20 min psi?
PCM voltage low, check battery cables clean & tight, running voltage at battery is?
Need to get a new NTK 02 sensor by the sounds of it-420.
Trans 0700 oh, have you serviced the trans fluid & filter?
Bill our electrical specialist will follow this post I've never swapped out the PCM, Bill can help on that one.

About 182,000 miles.
It would turn over fine, initially want to fire then barely a pop for 10 or 15 mins. I notice now it'll usually start fine if i give a little gas when first cranking. Battery looks looks new and the connectors look new also. I've been following advice from you guys and got the NGK plugs at .040. (Parts guy tried to tell me Dodge/Chrysler only likes Champion) but everyone here says NGK. Have not serviced trans yet guess thats next. I will get stuff for fuel pressure checks, ive seen that mentioned more than once here. Drove with the windows down yesterday and heard clicking noises from the front i think. Noise is intermittent but frequent. Its a new noise i think, vibration not so noticeable now, noise starts. Noise sounds like something is stuck to the tire, goes away, lessens, with braking,turning, accel, etc. Now im thinking CV joint instead of U-joints.

 

[LibertyTC]

It's always best to get an unkown battery load tested. What is the output voltage at battery? Use a VOM.
Giving it a little gas could indicate the IAC needs to be cleaned along with port. Keep IAC upright while cleaning with throttle body cleaner.
Clicking noises check for stone in tire, it's cheaper than a CV..but ya it could be CV. Any cracks in rubber boot or noticeable grease around?
Btw what did the old spark plugs look like? Any fouling or condition issues? Any pics of the old ones?

 

[JeepinJarhead03]

Re the vibration, a vehicle that's sat alot will often freeze up it's caliper slider pins. One of the caliper pins on the kj has a rubber bushing, at the least effort clean them out make sure they move freely and that only silicone grease is on them, worst case, azone sells replacement pins and bushings

 

[Joey D]

It's always best to get an unkown battery load tested. What is the output voltage at battery? Use a VOM.
Giving it a little gas could indicate the IAC needs to be cleaned along with port. Keep IAC upright while cleaning with throttle body cleaner.
Clicking noises check for stone in tire, it's cheaper than a CV..but ya it could be CV. Any cracks in rubber boot or noticeable grease around?
Btw what did the old spark plugs look like? Any fouling or condition issues? Any pics of the old ones?

I used the Innova scanner battery check routine and checks good. Noise mostly went away now. Puzzling. Here's a pic of one of the old plugs. When I saw what they looked like I was surprised that it wasn't ruining a lot worse. Gap was about .080 and center electrode almost gone. I'm going to try the cleaner today. Just keep trying stuff and changing things, will get it eventually and even now less things to go wrong.

 

[LibertyTC]

Plug looks carbon fouled. Plugs should be replaced every 35k. Once the gap gets eaten away, it wont run all that well.
Jeep's also don't like idling they need to be out on the highway once in a while to blow that carbon out.
Find some Chevron Techron Concentrate & add that to fuel, time for a highway carbon blow out.
If you are using ethanol fuels, find a good water remover to also add to the fuel !
Then up a hill put it to the floor, and watch to see if it's leaving a bit of black or brown smoke out the tailpipe. Mine does, if it 's been too long in the city.

 

[Joey D]

Plug looks carbon fouled. Plugs should be replaced every 35k. Once the gap gets eaten away, it wont run all that well.
Jeep's also don't like idling they need to be out on the highway once in a while to blow that carbon out.
Find some Chevron Techron Concentrate & add that to fuel, time for a highway carbon blow out.
If you are using ethanol fuels, find a good water remover to also add to the fuel !
Then up a hill put it to the floor, and watch to see if it's leaving a bit of black or brown smoke out the tailpipe. Mine does, if it 's been too long in the city.

It's actually a bad picture. Most of them were a tan color but the center electrode was half gone on most of them. The other electrode quite eaten away also which had the gap at about .080. I don't know how many miles since the previous owner had changed them but I wish I knew just because. I did use gumout, the regane stuff in it. I think it sat for like 2 yrs only occasionally being run. According to records I could find it was taken care of pretty well most of the time. 35K, I'll keep that in mind.

 

[LibertyTC]

When the Jeep sits for longer periods without frequent starting, the stem seals tend to dry up & more blow by can be expected.
A compression test of that cylinder next time may be a good idea.
Also I would recommend changing oil frequently (3000 miles) & switching to Valvoline High Mileage Max life 5W-30. It has stem seal conditioners.
https://www.valvoline.com/our-products/motor-oil/high-mileage-max-life-motor-oil
You could also add a small bottle of Lubegard bio-tech engine treatment into oil, it treats valve seals very well.
Allow the vehicle to always fully warm up.
Many also don't treat fuel for stabilization. Fuel can sour after a few months & also absorb moisture into gas, in the case of ethanol's.