ok, i drained my coolant and filled it back up as per the procedure in an effort to get any air bubbles out of the system. i followed the procedure, started the car up and it ran fine. raised up to about 170deg. then it got an idle like it was a big old pushrod motor with a cam in it. anyone else had this happen? is it normal? i shut the car off to let it cool and now im going to check to see if i have to add coolant. has anyone not had to add coolant?