My main has engineering, and I love to extract gasses, as she's a healer class and I can't kill elementals as effective. To make my life easier in remembering where they are I use extract gas. I love the addon, but since 2.4 it won't collect new nodes anymore. I shows the old ones I collected myself (no friend to share collecting with so I'm doing it on my own, slow but steady) but all the new ones I am finding won't show up on the map.
It's a little more work, but you can make a note (ie "/note xx.xx, yy.yy Gas Cloud (ie Swamp Gas)") and it will show the correct gas cloud icon on both the mini-map and world map. I think this is a better choice then downloading yet another data collection mod. ;)
I have had the same problem since 2.4. However, when I download the new Extract Gas, the addon does not show up in the cartographer user interface, and the previous clouds dont show up on the map. In the sign on screen to wow, I can see extract gas and it is enabled.
I disabled all add ons except for extract gas and cartographer and I still had the same problem.