Start up

96 v6 3.4. After sitting overnight won’t crank without a shot of starter fluid. Seems to be loosing prime. Also according to the math on the miles, only getting about 5 miles to the gallon

 

First problem sounds like the fuel line, tank to engine, is slowly losing pressure over night. Crack or leak somewhere? Any smell of fuel at all? the crappy gas mileage, especially 5 miles/Gal, sounds like you're dumping fuel / fuel leak. My guess.

 

This may or may not be your issue but the Denso fuel pump has a check valve in it, when they get old they fail even though the pump works fine, the fuel in the line up to engine drains back to the tank while the system is at rest. Some where on here somebody posted a denso fuel pump flow schematic, exercise the search bar and you may find it.
R/
Andy

 

Could be the IAC valve, clogged fuel filter, bad fuel pump igniter, pump relay. ANy codes?