1998 Mercury Mountaineer wont start when warm

Hi wisconsinner, Welcome to 2carpros and TY for the donation

it will only start the first attempt of the day,after that it turns over but will not start. Next time it refuses to start do below immediately to determine if its fuel or spark problem and get back with some results

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine atleast 3/16 away from ground-have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs,coil's resistances,distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it