After truck sits over night it won't fire for very long time if you continue to crank. Once it does start to fire it takes a while for all cylinders to pick up. It acts as though fuel has drained back. However one shot of ether and it fires right up and stays running. Checked fuel pressure and it shows 35 psi as soon as you hit the key. The colder the outside temp the harder it is to start. Had AvPro rebuild ECM and ran great for couple months. Then this problem. Any Ideas?

 

Check the fuel pressure regulator. 35 psi cold is low. The fuel pressure regulator should bump the pressure up to around 45 psi. Check residual fuel pressure also. The pressure should stay at 20 psi or so for 5 minutes after the engine is shut off.

 

I have the same problem. Changed the regulator and still having the same issue. Once it starts, It runs fine no issues what so ever. If anyone has the answer please let us know!

 

Dammit I spent 1/2 hour putting together some stuff on this and cyberspace ate it up when I posted!
I'm too busy now to redo it, but a) it's often electrical, b) Mazda technology gives rise to weird start behavior, c) there's lot's you can do about it, d) it's dirt cheap to do (provided the car has been reasonably looked after), e) even in the case of some defects, you can still trick the engine into life.