1997 Protege won't start?
 

I have a 1997 Mazda Protege that won't fire when cold. It turns over like normal but doesn't seem to fire until it warms up. Usually the battery ends up dying before the car will start but if I jump it with a running vehicle it will eventually start. I've replaced the spark plugs/wires, distributor cap, rotor button, even the distributor, mass air sensor and coolant temperature sensor and none of this have helped at all? Once the car finally starts, it will run just fine though.

if there's tons of miles, could be low compression or something major like that.

pull a plug after attempting a cold start and the plug should be wet, if not there's a fuel issue - like the fuel pump solenoid or corroded wiring / connectors.

you can also lay the plugs on the block and verify spark, should be bright blue and pretty wide (>0.5mm), if not it could be the ign coil.

Check valve clearance