Ok i have a s5 t2 that was having cold start up problems. Every time i would start the car it would take 6 or 7 secs of cranking for it to finally turn over. It would die right away when it would turn over so i had to feather the gas to keep it running. I checked everything..but the CEL said the coolant temp sensor was bad so i bought a new one..and reset the ecu or so i thought and nothing still had a rough time starting.

Then just 2 days ago after 2 months of this it started up right away but it would die when the CEL came on so i had to keep the gas held for little bit then it will hold the idle. Now what would cause this? Did i not rest the ecu correctly or what? Or is it very slowly fixing itself..lol

 

Nothing ever "fixes itself".
It is either working,half assed working,on it's way out or Busted!
Have you checked the connection to that water sensor you replaced?

 

I know the clip was cracked but it still seemed snug on there

 

If you got a CEL,then you have codes.
check the codes..again.