the codes it's thowing are P0456, P0440, P0300, P0301 and P0306. The first two I know are evap (and I know that it's the gas cap and a line that's cracked), and latter three I now are likely due to spark plugs. I changed them and now it runs even worse than before..they are gapped to the spec that the truck calls for.
as for the coolant, I have been keping an eye on it and it has not dropped.
New yesterday, it started overheating but the coolant level (as far as I could tell) was still normal.