[HO455]

The power piston spring Is what controls the part throttle enrichment. When at steady state cruising the engine vacuum is high pulling the piston and the metering rods down to the leanest position. When the throttle opens and vacuum drops the spring pushes the piston up and raises the rods richening the fuel mixture.
There are at least a dozen different springs that were used in Qjets and they all respond at a different vacuum level. When you call they should at the very least ask you what your manifold vacuum is at idle. If you were to know what the vacuum is at cruise that would help them get you the correct spring.
Having no spring probably means you have had poor light throttle acceleration and maybe some lean misfiring and or pinging.