94 Chevy k1500 misfire
 

I just replaced the fuel pump, spark plugs and wires, cap and rotor and thermostat. Truck was runnin fine until yesterday. I have a few oil leaks so I put non foul plugs on 3 of my plugs and the misfire got even worse. Any ideas? Plus ever since I replaced the thermostat I'm not getting a temperature reading on the gauge. I appreciate the help

Era not sure if I put this in the right section but any help is appreciated.