Rep Power: 0

I know the head gasket is leaking on this one, but not bad, but it has not had this problem until now. When cold it starts and runs with lower than normal power but its smooth, no missing, then once you shut it off and try to restart, even immediately after a cold start, it tries once like it wants to start but then nothing, just spins like no fire or no fuel, but cranking sounds normal. Tried starting fluid, nothing. Scanned it but no codes, I get a RPM sig of around 255 while cranking, No codes after driving it, while running live data all seems normal. 2003 Civic EX 1.7 auto IMMO is always working no issues.

 
Rep Power: 229

Do you have a live data scan of the temperature sensor? If they go bad they can mess up the fuel blend, while not throwing a CEL.

but test it first before replacing.

 
Rep Power: 0

I put on a new CTS and problem solved. These Honda don't take kindly to bad sensors. usually a bad sensor will maintain drivability.