Suburban intermittently starts. More so than not.

94 Chevy Suburban, 1/2 ton, 350, 5.7 litre
Changed out
TPS
Fuel injectors
Distributor, pick up coil, rotor, cap,
Spark plugs and wires
ECM
Ignition module
Fuel pump, fuel relay,
Starter
MAF
EGR
02 sensors
Coolant system
MAP sensor
Checked all the fuses
Its getting fuel pressure, the oil pump is working.
There is more I just can't think of it right now. I have basically have put all new under the hood

When I turn the key to the on position it lights up the dash, when I turn the key over to start the lights do not come on, the truck will not start, after a few tries I will hear a ding, the lights come on and the truck will start.
It has done this for the past few year at the same time, when the weather gets hot, the truck will not start, but around October the truck will start and run fine. The June-July rolls around and its the same thing all over.
I did get it started long enough to take it to the shop, the technician put it on the machine and told me its all in my head, it didn't throw any codes.

I bought a Chilton book and checked all the wires going to the ECM, they seem to be ok, except for a suspect orange one that seems to go nowhere.

I feel like I keep going in a circle when it comes to this truck.