Wram Motor Won't Start

2005 Dodge Stratus  2.4  4 cyl.  Auto Trans 
Sometimes, if you turn off the motor after it reaches running temperature,

it won't start until you let it set about 15-30 mins. (Starter spins
motor, 
no fire at plugs) It will start after that. Sometimes it runs rough after 
it restarts, sometime it runs find. Sometime the "Check Engine Light"
comes 
on after it restarts, sometimes the light does not.  Sometimes the "Check 
Engine Light" flashes.  Please tell me what you think could be the 
problem.... Thanks!