I've seen many posts about the immobilizer but none quite like mine. My car won't start if a)it rains really hard or b)it's really hot outside. I've replaced the ECM so it is not that. What sensor would cause this?

 

You didn't think of your cap and rotor? Not to mention you gave zero information about your vehicle.

 

What other information would you need other than the year, model and engine?