Sick of hunting down this issue on my own - Please Help! :)

[1LowToy]

Sounds like you have corrected one issue and need to move onto the next. Is the right side running rich? Try swapping the fuel injectors left to right. See if that makes the left side run rich instead. You may be dealing with a bad injector or a spark plug wire on that bank. Cold the computer is working of a fixed setting for fuel mixture. Warmed up (operating temp) the computer is in control of the fuel mixture (richer/leaner). Check the temp sender to the computer and the wiring for it. Did you say you had exhaust leaks as well? Your truck sounded pretty loud. Is your computer operating and giving you codes?