Check engine codes

[greenbean]

Hey everyone,
Got a 94 se 5 speed, check engine light came on. I ran the diagnostic, codes 34 and 35 came up as knock sensor and Exsahust Gas Temp sensor. It will idle ok at first then die if I don't keep the rpms up by using the gas pedal, also I think I have an Exsahust leak my whole pipe is pretty rusted out. Anyone have any ideas I pretty new here so all suggestions are welcome. It's pretty fun workin on this old truck.

Thanks