I am frustrated as heck trying to get this achievement. I have collected:

All cards, jumps, schematics
Finished all missions
All side missions
All races
All board jobs
Won all minigames at top level and all of Stanley's deliveries

I am ready to go to Capital Prime. But my counter is only at 128/130. All guides say that when you should be at 129 before you accept this and that beating the game gives you the 130. For the life of me I cannot find what I am missing. Anyone have any ideas?

My mission count on the jobs screen shows 59 completed, plus the two bounty jobs open and "talk to cpt marshall".

So you're just missing one mission/item? Umm, did you do the mission to bring the guy at the bar in Wellspring 20 Feltrites? I didn't even notice that mission til my second play through.

No I didn't and I thought I was missing something because I did that mission on my first play through on nightmare :\

I have two saves on this 2nd play through and I'd just sold all my Feltrites in the earlier one so I have zero. Anyone know of a way to get 20 Feltrites? Do those falling feltrite bonus things happen more than a couple times?

I haven't redeemed my sewer DLC because I read it's a waste of time, is there any in there?

yes there are some but not 20
the guidebook does have a quite a few errors

****.

So do you guys think I should start a 3rd play through or think I can get it with sewers/feltrite collecting minigame?

if youve sold your feltrite by the time jacob asks for 20 you are screwed. Even with the dlc i only found 14 more. Looks like there's another playthrough coming your way, lol.

I traded my 20 in and my character has 30 on him that I have found.

http://www.trueachievements.com/a155197/obsessive-compulsive-achievement.htm?showguides=1 might help you

I have a total of 68 feltrite. I could have easily hit 75 if I did better during the Feltrite meteor show mini-race.

Well I found another feltrite by the Outtrigger settlement but I need to find 9 more (since each one you fins gives you two). Maybe I missed some in some of the missions I can go back through? I don't know.

I will check the sewers next week for whatever I can find there. If there's really 14 or so in there then that only leaves 1-2 pieces I'd need to find elsewhere. Surely I left some somewhere.

If not, then hopefully some future DLC has feltrite because I am NOT playing a 3rd time

Or maybe someone will eventually make a guide showing where you can pick up everything. Dang I wish the merchants in this game were like Fallout where you can buy back what you sold.

I do not know if you need to do that guys mission defib or not? but i found so much feltrite you should be able to get it done still.
But if it isn't his mission that's holding you up - i know i did and I still have 128/130 not 129/130 going into the final mission. I couldn't figure out forever what I missed, every mission someone on a message board mentions I already did (and I am only on 1 playthrough so there is no chance i did it in a past game), but I have all trophies for everything, i did all mini games, went back and did them all again in both towns, jumps cards and schematics are 100%, job boards all done, races all won, atv goals complete, I couldn't figure it out. But then noticed huge GLITCH, I went back to Coffer the salesmen in Wellspring, and he has the damn sentry bot schematic again!? So even though i have Master Chef trophy says 19/19 100% found, and I know I used them in the game, and i load up old saves and i do 100% have it, since i have them and the advanced schematic, i cannot get to 129/130 before the last mission now. Unless that is just an odd glitch and is not the actual -1 stumbling block, but i have literally done everything else and beat the game one short so it has to be that error in the game. Dont know how or why it did it but I give up, no way i would do rocket rally's again for this trophy on another half playthrough (can load the save game before i got to subway town but that means all missions cards jumps and races in this half the game again just for a trophy? eh........). so they better patch it, i sent an email, and I have seen others mention this, but the game was buggy enough i doubt a few of us missing an achievement will be noticed.....

Just got obsessive compulsive! You need 130/130 BEFORE entering the final map!!!
The last point to get is the final jump right before the entrance to the last mission.
There are no points added in or after the final mission.

The info going around the internet that the final point to the 130 points is given after finishing the game is wrong!!!

According to the wiki, after you accept the Finding Feltrite side-quest, "the Feltrite Tempest event will be announced once you leave the Wellspring Entrance territory."

Also: "There is another Feltrite Tempest event that will take place in the area between the Scorchers territory and the Authority Prison after the quest "Liberate Captain Marshall" is accepted.

Here's the wiki page on the quest - unfortunately, no actual locations are given. http://rage.wikia.com/wiki/Finding_Feltrite