Bogging Down between 3 - 4K
 

Hey All, could use some help from the collective brain trust here. '98 SuperHawk, 24K miles on it, been mine for the past 4 years/10K miles. recently started bogging down between 3-4K RPMs. Before that range and once through that range, runs strong. The only things recently done were exchanging the stock gas cap for a vortex cap and added Stabil for the winter. Replaced the petcock diaphragm this Spring, could it be torn again so soon? Thanks in advance for any ideas on what to look at first.