So my engine makes a clicking sound when I'm at idle and when I drive it continues and then goes away. The truck did overheat badly, so I had to replace the upper radiator hose, radiator and all the coolant. I'm wondering if due to the overheating, could my exhaust manifold have come loose to make the noise?

Also have a P0038 code that came up today. Was told that might be the O2 sensor or the heater O2 sensor. Not really wanting to dump even more money into this truck to fix it, but I NEED to in order to continue being a 2-car family. What brand of sensor should I buy? Can I replace them myself? And I was told that I should use midgrade or premium gas at least one tank a month since I use regular gas (get better gas mileage). Any help would be greatly appreciated.

 

https://www.engine-codes.com/p0038_dodge.html

yes you can replace it yourself. Stick with OEM equivalent.