I have a 98 G Cherokee Larado 4.0 eng. 150k miles the problem is when the eng. is warm and I restart the eng. it idles rough and and has a rich mixture from the smell of the exhaust if I rev the eng. a couple of time it smooths out and seems to run fine still getting 18-19 mpg and there is no check eng. light. where should I start thanks

lbr