I need some help diagnosing this issue.
For the past couple of months i've noticed a slight change in the idle when stopped or parked. It would occasionally rumble but very lightly and every 1-2 seconds. It would appear normal to anyone else but i can tell myself that it didn't idle like this before. Now it's starting to idle rough, motor rocking and tossing the jeep, when I first start it up until the oil pressure reaches normal, about 3-5 seconds. It starts up just fine and then idles normally after this happens. What could be causing such an erratic and rough idle the second you start it up and only for a few seconds?
It's a 2001 XJ.
Thanks!