Engine is hunting!?!?

[tysonVL]

Hey All!

Off and on it's hunting and doesn't idle smoothly. Just wondering what your thoughts were on possible causes of this? It seems to happen randomly, not triggered by anything but when it does happen it generally starts when the engine has warmed up, not right on start-up.

[VR38]

Maybe check the fuel pressure, I found the age associated with the RB series the pump/s and the reg suffer.

[detox_nath83]

vac leaks or air getting in the piping after the AFM can cause this as well