Hope someone can help. Wife has the '04 GC with 4.7L HO AWD. We've had it to the dealer, (tune up at 40K miles w/platinum plugs) and still when you first start the car is when it's the worst. Has a rough idle. When the RPM's are raised it smooths out. Still averaging ~18 MPG...but the rough idle is a nusiance.
Took the car to our local service center. They could find nothing wrong! Cleaned the throttle body and added a cleaner to the tank. Still NO good. Wife loves this Jeep!
Hoping someone has lucked into the problem and knows the fix. Dan in TN