once it heat up its take time to start up?????!!!!!!!!!!!

[anujan]

hi i bought used rx8 from a private owner 2005 model 54k 192bhp 1.3.when i bought it was little misfire,when i checked i coil fail to supply power.i had changed all new mazda coil,leads and spark plugs,now i m having prob if i runs smooth for a long drive over1hr or if i accleratr to 6000rpm for a min,after i stop cant start immidetley!!!i have to wait for 10 - 40 mins.it will crank bt wont start or i have to crank for too long(which is not good for engine).still lite misfire on engine,but no warning sign on dashboard.good oil,coolant level.what could be the prob?could be cranksharft sensor pro?or as it engine prob?dose uk mazda also covered under 8yr warranty?(scratch)