My 2004 Mazda 6 won't start when it's cool outside, even under 70 degrees. Mostly it starts but randomly when it's cool outside, it won't. There appears to be nothing wrong. New battery, it turns over, can hear the fuel pump start, and later when the day warms up itstarts. This is very frustrating.Has anyone had experience with this? Thanks

 

A friends of mine is doing the same thing , Some one here has to of run into this issue before

Tom

 

Is it cold and damp? You might need new spark plug wires.

 

I know this thread was back in 2008, but I am having this EXACT issue right now with my car and have no idea what is causing it! If any of the older posters are still here, have you ever figured out what caused this, and if so, what was the solution?

2004 Mazda 6 S MTX

 

Just a thought, get your coolant sensor/sensors monitored. You may be getting a faulty signal, telling the computer the engine is hot when its cold & not supplying enough fuel for a cold start.

 

I looked around a little more that day and came across another thread where it was something with the ecu having a fault of cold or cool weather affecting it. I have tested this the last couple days since it has been cooler than usual where I live, so I've been using a heat gun to warm up the ecu inside the car and it has been starting up perfectly for me...