Numerous misfires!!!

[Fightingirish1050]

I own a 2010 JK Unlimited w/36k miles. It has been at the dealership now for 19 days due to numerous misfire codes during diagnostic testing. The dealership stated they cannot determine what the problem is and are starting a Chrysler "Star" case. Has anyone he'd this issue before and also
has anyone been involved in a Chrysler "Star" case?
Miss my jeep

 

[SteelHeadz]

I'm going to assume that you have a 3.6liter on your jeep. There's several contributing factors on a P0300 when diagnosing that issue. Since its in a dealership, I would also assume that they've done a cylinder leak test per service diagnostic procedures with known service bulletins. In most cases I've found it to be more mechanical than electrical however, the basics of diagnosing a misfire should not be overlooked. Which cylinders are affected and what DTC'S are active?

 

[Fightingirish1050]

It's a 3.8L. It started off with cylinder #3 but now it's numerous cylinders. They did conduct test you mentioned. They claim that every time the light comes on it is resetting itself so they are unable to verify the issue. They also tested the EGR valve aswell with no issues showing......

 

[SteelHeadz]

Wow 3.8?, that's unusual. When they said it was "re-setting" , do they mean the PCM is not storing the DTC'S or is it the OBD misfire monitor on 200 rev.cts that's resetting? . If it's the PCM resetting, I would say this is an electrical issue.. I've haven't encountered much issues with the 3.8 liters with misfires. The Linear EGR can cause erroneous misfires however, the dealership Chrysler diagnostic computer(Witech) can test that EGR if its faulty. One more thing to check is the camshaft lobes , rocker arms and hydraulic valve lash adjusters for abnormal wear. If there's a knocking noise at a higher RPMs on the cylinder head area, have them check the camshaft towers for cracks.