Need help with my 2007 Wrangler unlimited (misfire issues)

[grandall1972]

Picked up a high mileage 2007 wrangler unlimited. It's a 2wd, that will be 4wd eventually, but I got it for a good price.

When I got it it had a miss under load, tried to drive it home and after 15 miles it turned into a constant miss.

Codes and issues
1. Codes p2308 and p0300 misfire codes and coil secondary C codes
2. Also codes for emissions guess from running with two cylinders not firing.

First attempt and results
1. Replaced coil
- no change
2. Replace wires and plugs
- no change

Noted issues and possible resolution
1. Getting no spark to the 3 and 6 cylinder
- Thinking PCM is the culprit now.

Questions
1. Does this sound like a bad PCM or something else?
2. Anything else I should look at?
3. Do I have to get the pcm programmed if I replace it?

 

[Kyzrsoze]

Which engine does this one have?

 

[grandall1972]

Which engine does this one have?

3.8l

 

[libertysteeth]

Did you try different ammo?

 

[Cadcom]

Can you disconnect the PCM completely? That may fonce it into a limp home mode and maybe you can see if the misfire is still happening. Maybe.

 

[Kyzrsoze]

How clean were the plugs that came out of it?

 

[simonsez]

check the crankshaft position sensor.. that is what it sounds like to me.

A bad crank position sensor can worsen the way the engine idles, or the acceleration behavior. If the engine is revved up with a bad or faulty sensor, it may cause misfiring, motor vibration or backfires. Acceleration might be hesitant, and abnormal shaking during engine idle might occur. In the worst case the car may not start.

 

[Bonecollector]

Your sir may have a lemon on your hands...

 

[grandall1972]

check the crankshaft position sensor.. that is what it sounds like to me.

A bad crank position sensor can worsen the way the engine idles, or the acceleration behavior. If the engine is revved up with a bad or faulty sensor, it may cause misfiring, motor vibration or backfires. Acceleration might be hesitant, and abnormal shaking during engine idle might occur. In the worst case the car may not start.

I've considered this as well, and might try it first. There isn't a misfire though really. There is no power/fire going through the wires for cylinder 3 and 6. Checked other wires and they fire great.

 

[grandall1972]

Your sir may have a lemon on your hands...

Possibly, but I'm good at making lemonade. Just hate chasing electric ghosts. I got it for a steal, and if it comes down to it, I'll do an ls swap along with 4wd conversion.

I know it's electronic, but unfortunately that's the hardest to nail down.