If you farted in space would it linger?

No, because it would be in my space suit. Ewwwwww!

Yes, near Uranus.

Only in your space

Assuming it were possible to fart and release it into space (which is impossible since we can't exist in the vacuum of space to be ABLE to perform this action)...but IF it were possible...the force of the fart itself would theoretically continue moving with the force it was ejected...and since space is a near-vacuum, there would be little to obstruct its flow and no air for it to mix with. Therefore, it's logical to expect that it would not linger but rather, it would move away in the direction it was "fired" and continue to do so for quite some time, until it mixed with the normal molecules of space.

You'd have to release a done fart or you'd explode ripping one in space directly, but when released the few molecules would follow the laws of Thermodynamics and disperse as widely as possible and after a few hundred meters there would be a few molecules per cc. The equation [Ideal gas] you'd use is:
PV=nRT, and solve for n/V=P/RT. I'm not doing this for free[ed]. Soon there would be little that could be done to find the individual molecules that blast would become.