Hi, I’m a level 35 and I finally got the NCR to be neutral with me but some of them still shoot at me on sight. Mostly the rangers.

Any tips on a few quests or group of people i can kill to help get a little positive with them?

Take of the faction armor.

Did that LOL. I even went in just the shirt and boxers but still some of the NCR try to kill me. I’m starting to wonder if it’s a glitch or if it’s just because I’m a “Low Neutral” with them. I think if I do one or two more quest I should be fine but can’t find any.

If you failed "Don't Tread on the Bear" with the Legion, you can never work with the NCR anymore. If your reputation is the cause of the NCR attacks, then you can wear disguises to get your reputation up or get the pardon from the NCR ambassador. Maybe you shouldn't have attacked and stolen things from the NCR to get such a low reputation

Have you tried putting the faction outfit on and off again.
As Warpenergybot posted have you failed the don't tred on the bear quest.

Also to boost rep if on a unbugged game do Sloan / quarry junction.
Do Crimson caravan quests.
Do the Bitter springs area quests.
Try Camp Forlon Hope.
Try the Helios one quest.
All favouring the NCR.