99 4.3 vortec p0300 white smoke
 

Hi I'm new to the forum. After exhausting the search feature I've decided it's time to post. I recently replaced the head gaskets on a 99 blazer that has been sitting for 3 months with coolant/oil mix in the crank case. It started up and drove great for a while (2days), but would die while making a turn or braking. It has since become hard to start and has a P0300 code. When it does fire up it creates a lot of white smoke which doesn't smell like coolant. The coolant level has also remained unchanged. The fuel pressure was low (x<60psi) so the pump has been changed. Now the pressure passes prime and watch for 5-10min test. New cap, rotor, plugs and wires have also been installed.
Some additional freeze frame info from a scan tool is:
STFT b1 50%
STFT b2 33.5%
Map (mmHg) 15.6
TPS (not open) 0%
RPM 611

If a high STFT is a lean condition, could that mean the injectors are clogged/leaking?
My next thought after searching the forums was to look into the spider assembly unless someone has a better suggestion.

Thanks you for reading,
Glenn