Hi, thanks for some ideas...have both temp sensor and sender (just purchased), and on my worklist. But why would distributor be the problem with fuel and mpg? and...How do I determine if the converter is plugged?
Thank you for the input!

HISTORY 1993 SAFARI AWD VAN 4.3L vortec, MFI , engine-W, 93,000mi Since purchase (2015) -complete tune up-wires, cap, rotor, all fluids incl all driveline/cases, all filters, coolant etc etc (5500-7000miles ago) -got 21-23mpg highway, 19 otherwise (for about 5000miles) -On a summer trip to sequoiaNP...