I've been reading on the forums about the fuel pump relay and the master relay causing trouble. Here's why I must ask the question: the car used to not start (it would crank strongly but wouldn't start, like no fuel, etc.) in the morning when the outside temp was in the sixties. This happened 3 times in two weeks. I changed the coolant temp sensor. In the last week the same failure to start happened four times but each time in hot weather. Once about four days ago it wouldn't start early in the morning also. Of course after five or so min, the car started easily. Is it the main relay or is it the fuel pump relay or something else? What do you think, please

 

sounds like the main relay under the dash i had the same issue then i replaced the relay and problem solved

 

So you had starting problems both at cool and hot ambient temperatures? Or was it only when the vehicle was hot?

 

both cold an hot but mostly when it was hot

 

That seems to be exactly what is going on with mine. Thank you so much for the input.

 

are you sure that you are getting spark?