I just did a heater core flush so the heat would work better when the hard winter hits but when I started I was all fine for about 5-7 minutes it just shut off randomly and won't start up again. Its been having a rough starting issue ,you would crank for about 5 seconds and it would sputter for a little then come to life -if u blipped gas would also start immediately-, would start back up if you turned it off and then cranked also smelled rich when started. Tach reads zero when cranked and no codes have popped up.i have tried feathering flooring the throttle and still nothing.Could I have fried the ignition coil while flushing? Or is just possibly injector issue , or even CPS.