98 ram 1500 5.2 2wd will start cold but won't stay running after warm. temp guage doesn't work but everything else seems to. usually will start back up if hold throttle to floor and stay running if rpms are held around 3000. i am beyond lost and frustrated. have changed almost every sensor on the engine. what the heck do i do

changed tps, cam sensor, crank sensor, idle air control, throttle body, coil, plugs
and cap & rotor. have fuel pressure. gets gas. starts cold after sitting for a day
or two, it fires right up. once warm, it dies when shifting into gear and either
won't restart or only starts if holding throttle to floor and dies instantly unless
holding throttle to approx. three thousand rpm