2008 Grand Cherokee Stalling, but always Restarts
 

I'm Posting this up because I want to be able to help keep people from pulling their hair out.
I recently had to diagnosis a 2007 Commander Overland that would stall intermittently and always restart, Dealer had it for 12 days before they sent it to me. I asked the owner what if any service he had performed prior to the problem and he told me he had the spark plugs replaced and the EGR valve replaced. The dealer replaced the PCM, the Ignition switch and key fobs, and a complete engine harness before the owner decided to bring it to me.
After some research I found that Chrysler had a No Start/Stall campaign but the information was vague and incomplete.

2007 and newer Jeep G. Cherokee and Commander equipped with the 5.7L Hemi engine are extremely sensitive to Radio Frequency Interference from the waste spark on the coil. The waste spark generates a radio signal that in most cases is harmless, however on these vehicles they use a wireless communication module for the security system (keyless entry and theft control). This system constantly verifies with the PCM(powertrain control module) that the ignition signal is true, when it detects 2 incomplete feed back responses between the PCM and the WCM(wireless control module) the PCM closes the ASD relay(auto shutdown) and the engine stalls, but restarts as soon as you cycle the ignition key.

The correct Spark plug to use is the Champion 570 Copper Core Plug. However, manufacturing tolerances are too high and the resistance values between new plugs is 3 to 35 ohms. You need to check and verify that all 16 spark plugs are between 3 to 5 ohms....no exceptions.
The use of platinum plugs is not recommended or suggested for these applications, and although there have been cases where they where used and no trouble was experience....the fact remains a constant..copper plugs only.

I will post some pictures on how to correctly verify the new spark plug resistance.

Very interesting post, Willys! I'm sure anybody that reads it will find it amazing that something like this is possible. It just goes to show how much today's electronics is involved in our vehicles, for good and bad!

I remember back in the 60's with carbon core ignition wires, if replaced with copper core, the radio would go nuts with static. That was AM radio.