Ok, good no milkshake signs on the oil dipstick, or oil fill cap.
Get the scantool back on the engine to look for additional pending, or set trouble codes & post All code clue Numbers found.
I'd also consider having the scantool hooked up before the next drive, so it can capture a full snapshot of the drive cycle, as the results could help focus your trouble shoot.
With the scantool, have a look at the MAF
PID's & the long & short term fuel trim Numbers & post them up for review. Sounds like you may have more than one problem confusing things.
Did the popping sound sorta like back fire, or spit back through the throttle body, or was it a mechanical sound????
Lack of power sounds like fuel delivery mischief, but could also be timing, or a clogged cat converter causing excessive exhaust back pressure, so maybe any stored, or pending codes could offer up clues on where best to look next for suspects.
What was the set trouble code Number that was said to be for a sensor???? If you don't have, or can't remember the code Number, what sensor was it said to be for/what sensor was said to need replacement????
Ignoring a CEL/SES warning light for months isn't good practice, as if the warning was for a faulty O2
sensor, that cyl bank fuel trim could be so corrupt as to cause cat converter over heating & internal matrix meltdown & that can cause excessive exhaust back pressure when you go at throttle up, or climbing a hill & cause a lack of power. It'll also cause excessive engine heat/maybe why the temp gauge spiked/maybe why you heard popping on the latest drive????
Hook up your vacuum gauge & perform the restricted exhaust test in scenario 14 here How to Use and Interpret a Vacuum Gauge
If the cat converter is clogged, it'll typically glow cherry red when it over heats, so have a look underneath at the cat converters next time you drive it & it doesn't want to go at throttle up.
While the vacuum gauge is hooked up, also perform scenario 13 for blown head gasket.
If the problem was serious & ignored for months, it could have caused more problems, so good that your having a go at diagnosing the problem/s.
Keep us posted on your findings.