Running badly until at operating temperature
I have a 2007 GMC Sierra with a 4.8 liter engine. When I
start the vehicle it idles fine then after a few it drops and
seems to skip.... if it is cold outside it will run fine but once
it gets a little warm it starts running terrible loses power
and spits and sputters but once it reaches normal
operating temperature it seems to run fine... check engine
light is on and when driving even after warmed up it will
flash and then will stay lite then flash etc.... I have
checked codes at oriellys and have replaced the cam
shaft positioning sensor ,the number 4 coil pack, the
plugs and wires and still no change... I have also cleaned
the throttle body and I am at a stand still as to what to do.
Any help would greatly be appreciated