Will not start when cold

what is the fuel pressure with key on and engine off? since you mentioned spider injector assembly it has to be a vortec engine that requires 55psi to open the poppet valve in the injectors just to start.

Your jeep ecu is in need of repair. It has what is referred to as the delayed check engine light problem. If you'll notice, next time you try starting the jeep, it will not start when the check engine light finally comes on, on the dash. The fuel pump will only come on when the ecu finally energizes the relays, and that's when all the clicking starts. Look on ebay for an ecu repair service.

The first thing i would tey is changeing the fuel filter. Chevy has a problem with the design from the fuel pump to the fuel inlet on the intake manifold. What they did it is back up the power supply to the fuel pump from the fuel relay and split the curicut and ran the back up through the oil pressure sending unit . So even if the relay went bad while driveing the fuel pump would still get power and the truck wouldn't die on the road its a saftey thing .But if the relay is bad then the engine needs to build up enough oil pressure to trip the oil sending unit to send power to the pump from cranking thus a long cranking time when cold . Change the fuel filter first it should be replaced every 4 to 5 years anyway . A nd if that dosn't fix it try the relay it should be behind a panal inside the glove box on your truck and if that dosn't work replace the oil pressure sending unit. One of these 3 things should work if the fuel pump is working correctly

I'd be looking at fuel pump. It works when cold, but as it spins up, it gets warm then shuts down from excessive heat.

starting definately has a lot to do with the crank/cam position sensors, but it wouldnt have nothing to do with hot or cold weather, oxygen sensor will make the vehicle run too rich if its out, you will smell fuel very strong out the exhaust, that could make it run sluggish also, and usually if the mass air flow sensor goes out the vehicle wont start at all...

when it does not start you need to verify no fuel pressure, Most likely your problem is the wiring harness is bad which will destroy a new pump if the pump is not geting the voltage required.

Your cold start valve is not opening to assist the firing. It function is to provide extra fuel to ignite the all combustion chambers easily. When the engine doesn't have this extra fuel from the cold start valve, it will take a few times to get it going. The cold start valve is turned on at the time of starting only if the ECM get the signal from coolant temperature sensor saying it is at a preset level. When the sensor is bad, it can give a wrong value so ECM think that temperature is hot so not turning the Cold start valve. Replace this coolant sensor first, then the next thing is to check out the cold start valve.

Does the fuel line still have 55 PSI when engine warmed up? Any other codes show up?

Fuel pump is a possible cause but I would check the ignition timing first.

change fuel filter if you have then change fuel pump