Finally found the source of my issue...an intermittently functioning electronic fuel injection relay. One day when the engine wouldn't start I touched the top of each relay related to starting, feeling for the telltale click. All checked out except for the efi relay. Replacing that $15 part seems to have solved my problem, perhaps it's the same with yours.

 

Thanks for the follow up. hopefully it will save others time

 

As Jim Bailey famously says, "relay, relay, relay!" Glad you found the cheap, easy fix.