Welcome aboard. pull the yellow wire off of the starter relay to disable the starter & have a helper hold the key to "start" & see if the coil positive primary terminal/blue/yellow ECU terminal are hot (& near batt voltage) then have him release the key to "run" & see if they are still hot. seperate/reconnect the ECU pentastar connector/dist pickup zigzag connector & firewall bulkhead. Ohm the dist pickup for ohm amount/continuity. the coil positive primary should have more voltage than the coil negative primary terminal. How did you wire it up? this'll get us started. EDIT with a bit more thinking, you might be wired right ex the coil is backwards & it was OK when warmer but not when it got real cold OR the ECU mighta failed (it wouldn't be orange in color would it!). Ohm the ballast too but for that potential that would be a "run" side issue with maybe a hint of starting on the "crank" side till you let off the key & it goes back to the run "ballast" side.