DTC codes, vehicle running rough

[Gulf550]

Thanks for the idea Matt. So what I did this morning was return it back to stock tune. I rechecked the fuel pressure with the vehicle running this time and got 59 psi. The previous reading was with the ignition set to run. I have taken it for a couple test runs, interstate and country roads varying speeds from 45 up to 80. No codes have reappeared and I'm getting a lot better gas milage. Before with the tune installed I average 11 and 12 mpg, with stock tune it jumped up to 15 and 16 mpg. Only time will tell though. The plugs I removed were the worst I've ever seen, they have only been installed for about 30,000 miles. I'm wondering if running the 91 performance tune caused all my plugs to foul. If anything changes, I will keep everyone informed. Thanks for the help.

[07JeepXK]

Hmmm I have an 07 4.7 liter and just hit 150,000 miles today. I have been running the 91 performance tune for well over 3 years with either 91 or 93 octane gas and haven't had any issues! What plugs do you use. I've found out that the OEM champions work best for my jeep. I'm getting almost 13 mpg city and I'm running 305/70R17's. This weekend on a 6 hour drive to play Army I got up to 16.8 mpg with cruise set to 65 mph.

[Gulf550]

I was using the OEM ones. It was just wierd how fouled they were. Don't really understand why. Only thing I could think of is because of the tune. I will drive around on the stock tune for a while and keep checking them.

[07JeepXK]

How long have you been running the tune?

[Gulf550]

Right around 4 years now.

[07JeepXK]

So why would it just start running bad and getting codes if you have been running that tune for 4 years

[06JeepXKHEMI]

I did some research for you about tunes and gas etc... This is common for people who use low grade gas or not high enough octane for the tune. Not saying thats what you did but these symptoms are.. What gas station are you using? Are you sure the tune was for the 91 tune? It was only a short period of time but I ran the diablo intune 91 tune and had no issues and when i checked my plugs they were damn near perfect. I only ran Sunoco or Mobil and beat the piss out of the HEMI to be honest..