Have a slow starting mazda 6. As recently as last week, everything was fine, and then it just started to take longer to start. Battery and all other electrical is fine. It just cranks over longer before it will fire up. Takes from 5 to 15 seconds before it will start. It runs fine and will start a bit quicker when it has just been shut off. I don't think it is the fuel pump, thinking that it may be some sort of a regulator or something that keeps the fuel pressure up. Mazda dealer wants $100 just to diagnose it. Any ideas?

 

Mileage?
Any services other than oil changes?

 

84,000. miles. Perfect running car up to now. Never any service lights either.

 

WTF is a service light? It's hard to find good help these days!
Any services other than oil changes MEANS have you ever had the spark plugs changed, have you ever changed the PCV valve, have you ever put in fuel cleaner, have you ever changed the coolant, have you ever cleaned the MAF or throttle body, or EGR valve.
If you have said no to the above, do them.
If you haven't changed your spark plugs yet, change them as well as ign coils (while you are there because chances are they will fail before you have to change your spark plugs again).
If you haven't changed your transmission fluid, change it. Same thing with power steering fluid, brake fluid. These fluids will have nothing with your problem but must be done unless you want to buy a new transmission and other stuff in a few years.