Cold start problem

I have a 1994 Jimmy 4.3, 180,000 miles, with CPI. The truck will not start when the motor is cold regardless of ambient air temp. Usually when the truck sits over night. Turns over fine and battery and charging system work fine. It will only start with a shot of ether and once running the truck runs great. I have recently replaced the CPI injector. Replaced fuel pump about 10,000 miles ago. Also fuel pressure is fine at power on and while running, about 60 psi. The wires ,plugs, cap, and rotor are new. The coil is about two years old and test resitance and checked for arc on a humid morning, and coil seems fine. Also the o2 sensor and engine coolant sensor are new. The plugs show no signs of lean fuel while running or excess fuel at start up. Plugs look very clean. Also i have checked for vaccum leaks and found none. Also i checked voltage to all sensors on the motor and found all were receiving 5.0 volts. Also checked all senors for resistance and all were with in the correct range. As far as i know i have covered all bases but if i am missing something please help!!!