It can be any following items:
-AFM
-Fuel regulator, pump, tank
-Temp sender (the blue one mostly)
-Distributor (yea, i'm having a lot of trouble with those lately, check
inside, remove dust cap, check wires/hall sender), check the cap, inside,
the center pin should spring OUT, easily, check also the ground on the same
harness (top of left head)that goes to the distrubutor, check the plug aslo.

OS could do that but you said it's ok?

Ben