the pinch test yields about 2 1/2 seconds
thats telling me your LSN is running too lean and needs richening. If you have been richening the HSN then wouldn;t really help the situation. With the pinch test the idle should increase sharply and then take about 5 secs to quit. 2.5 secs is a little too fast and the LSN is most likely whats causing the lean bog at less than qtr speed.