[ossiblue]

#1. Agree with 1990C4S, check your fuel pressures.

"10s" cranking? Does that mean you are cranking the engine for 10 revolutions, or the engine is cranking for 10 seconds? Either way, you should get an immediate firing if your cold start valve is functioning so check that next for operation. (If you are cranking the engine for 10 seconds you are risking flooding and hydrolock--be careful.)

#2. Stalling with a pop when cold indicates lean mixture--related to high pressures or air leak. Check all the usual suspects. Having to lift the air meter may indicate the meter plate needs to be adjusted--this could account for hard start also.

Do you have a pop-off valve? Maybe the valve is sticking open when there is a backfire and when you remove the air cleaner to move the air plate, it snaps shut--this can happen if the valve is installed incorrectly, with the hinge facing toward the front of the car.