Vehicle:2000 LT 4-Door 2wd 4.3L Auto 131,540 miles original motor rebuilt 4L60E

Work and Why:This weekend I changed valve cover gaskets. heater hoses, changed thermostat & rubber gasket, rotor, plugs, plug wires, oil filter. She was due for oil & filter, water neck around thermostat had a small leak, heater hoses just looked weak and passenger side valve cover was leaking
Radiator, water pump & thermostat 8 months old.
Finished up no water leaks, radiator full, no oil leaks, oil full, runs smooth and quiet.

Problem: Oil pressure gauge shows no oil pressure, temperature gauge will not move and after warm up, if you shut truck off then restart it doesn't want to start right up? 10-20 seconds turn over, hit gas pedal, starts, runs rough for few seconds then smooths right out and runs great.

I let it sit in driveway idling for 30 mins neither gauge moved
I ran it around town 50 miles today ran great with exception of restarts and gauges not reading

What am I missing?
I looked at harness I put all connectors back.
Did both my gauges go bad at same time?
Help me out please I'm missing something?

 

Update: Cleaned & WD-40 2-wire temp sensor and plugged back in. Truck runs perfect & has fuel mileage again. Must had moisture in contact or bad contact I don't know but cleaning and spraying contacts cleared problem up. Starts warm and cold great. I read and learned about 2-wire temp sensor in this forum. Thank you for being here.

I still have no oil pressure?
I'm going to research the oil pressure switch and gauge in the forum and see if I can get lucky again and have a "no cost" fix.