Bad Idle When Car is Warm?

i have a 93 plymouth sundance with a 2.5 litre throttle body injection. and when its warm it has a pretty rough idle but when cold it runs perfect. it is sometimes hard to start like itll start than die than i have to pump the gas to start it again and that only happens sometimes when it sits overnight but i dont know if that has anything to deal with the rough idle when warm. i did get in a accident a couple months ago and replaced 2 of the 3 motor mounts. the 3rd one is a little cracked so i need to replace it but would that cause the car to idle rough only when warm? it only does it in drive and reverse and reverse is worse than drive... i also get very bad gas mileage and i mean bad as in 14mpg. the bad gas mileage was there before the car accident. i have changed the injector,wires,plugs,cap,rotor, and o2 sensor just as normal maintenance but it hasn't helped neither gas nor rough idle... could the computer the problem? oh and the check engine light is not on and there are no codes.