My wife has a 04 mazda 3 4dr hatch, automatic. it has developed a problem starting. You have to crank it a long time and it either starts with a rough idle at first then runs fine, or if you crank it, then reset the key and crank again it starts and runs fine. I have replaced the basic's like plugs, air filter, even ran some sea foam through, same deal. Please reply with any suggesions. Thank You - Rick

 

Sounds like a leaking fuel system to me - or maybe a crank angle sensor, though that would set the CEL.
If the fuel system is leaking, like leaky injectors - leaving too much fuel in the cylinders so it's a hard start. When it does start, is there any smoke out of the exhaust?