I know our Cherokees have one, but I haven't been able to find out where it is or really how to service it. When I stop to fill up at a gas station, I get a very large WHOOSH of pressurized air coming out of the fill neck when I remove the gas cap. I'm assuming the vapor recovery system is clogged and needs to be serviced.

I'm also noticing sometimes when I start it up that it idles extremely roughly, but smoothes out if I give it any constant throttle. After driving for a few minutes, it's fine. Backing out of my driveway, it does this at the bottom (my driveway is a smal hill), but clears up as soon as I put it in drive and take off.

Direct me!

 

Bumpage.

 

Bump to the top, for great justice.