Nothing else you can do except bug Jeep Customer Care some more times.
Unfortunately, Jeep removed the schrader valve on the fuel rail on the '08 model year. Not so easy to check fuel pressure it anymore.
However, I would guess that fuel pressure less than required for spray atomization would result in an out-of-spec reading at the O2 sensors and/or cylinder misfire codes (ie, DTC's).
Since the engine runs otherwise normally, it is unlikely (but not certain) that the fuel pump/filter in the tank is at fault. When my injectors started going bad, I got sporadic misfire DTC's. We relocated specific spark plugs and injectors and were able to trace the DTC to several injectors. Eventually all fuel injectors had to be renewed. The full suite replacement. plus clearing an exhaust leak ended to DTC's.
You are not reporting specific DTC's in this are, so bad injectors seems unlikely. Also, I didn't read that you verified dark upper electrode connections (to the coils) on your spark plugs. Certain of the Champion 570's have silver-colored upper electrodes. MOPAR's Star Case says these are not to their spec. Only have to pull 1 coil pack to see which color you have installed.
One thing your dealer can do is equip your Heep with a "flight recorder" on the OBD2 port. It will collect the last 3 trips and can be started recording if a problem develops. The results can be read on their StarScan and downloaded to MOPAR if necessary. I understand that it's not generating DTC's, but maybe the recorded engine parameters will provide MOPAR a clue towards establishing the root cause.
Thanks for all of the info Walt. I spoke to the Tech and he advised no codes in the computer at all. They found 2 codes in the history (1 for seat and 1 for radio). It is almost like the stalling "never happened". The plugs are the black top-I have the old ones as well as they were black top too. Coil packs are brand new.
I will ask about the flight recorder. I s/w the dealer Friday and he said they were going to drop the tank and look at fuel filter/pump as it acts like it is running out of gas in the videos... He said possibly a baffle in the fuel filter?
I will update as I get more info. Been a week in the dealership already-temps above 32 degrees all week and no stall, so they haven't been able to replicate the issue. It does happen when it is below freezing-did it 3 days (all below freezing outside) in a row if that means anything.
I will update as I get updates. Thanks again everyone.
Last week, the replaced the fuel pump. Nothing out of the ordinary in tank and no notable issues with old pump. The mechanic wanted to rule this out all together. The Jeep ran fine until 2 days ago. I had to come to a hard stop in traffic it tried to stall out and then "lurched" forward before the rpm's rebounded. It almost felt like I was driving my friend's manual Jeep and stopping in gear. I filmed it again the next day (thurday). Here is the link-for whatever reason, the video is sideways.
So I have received the information on the flight recorder findings. I was able to record 2 bog down instances and 1 complete stall. The data was uploaded and according to the engineers the computer is "being reset". I spoke to the dealership and they are not sure what is causing the "resetting" of the PCM, which causes the vehicle to bog down and at times stall. Whatever it is, it is badly affected by the colder temperatures. Since it hasn't been as cold as it was, it hasn't done it.
So picked up the Jeep last Friday. They found a code for transmission after doing emissions test-I can post code later. The issue was inside of the valve body and shift pack. Their were metal shavings found within the valve body and a bad shift pack seal. The seal wasn't holding pressure and when coming to a stop in the cold the transmission would apparently lose pressure and bogg down and stall out the Jeep!
Since the repair, has been in the negative degrees and so far no issues. Only time will tell, but figured I would share.
SHIFT PACK? What did they to ameliorate the issue? Did they replace the transmission? If there were metal shaving in one part, there are metal shavings all throughout it. if they didnt pull the transmission, completely disassemble, flush the cooler, lines, replace the torque converter and replace the clutches, seals, gaskets and electronics, then you are bound to have issues soon.
Daniel J Fenti
Owner - NC Transmission
2004 WJ Overland lightly modified
Boat Drinks OffRoad Co-Founder
Here is another point of concern-look into where the wire harness sits on top of the engine. When the resonator is placed back on top of the engine-it tends to push the wire harness right on top of the coil packs. As mentioned in previous trends-this tends to be a problem with EMI and a quick thing to check.