Originally Posted by bpowa
i use champion platinums.. not the double. however it came with ngk platinums.. i have an 05 and it has no wires.. and uses individual coils..
You should definitely
be running double-tipped platinums in your distributorless '05 and not those single-tipped platinum plugs.
The new coil-on-plug design used on later distributorless 4.0L engines use doesn't do well unless both sides of the spark plug gap are identical. Jeep has issued a TSB (technical service bulletin) that upon receiving a Jeep with a bad idle or other hard to diagnose engine running problem, they are to check to make sure single-tipped platinum plugs are not installed and replace them if they are.
You should be running either non-platinum plugs or a double-tipped platinum plug like the Autolite APP985.