About 2 weeks ago I parked my GT to change the cam seal as I had an oil leak, that's finally taken care of. Once I got the timing cover off however I noticed that the timing belt badly needed to changed and could jot in good conscience put it hack together with that belt. Jump forward 2 weeks later the car drives and seems to be ok, but I have about half an inch play in the belt that I can get out. This is however much better than where I was at last week. The only thing I can think if is AutoZone gave me the wrong belt. Any ideas or input would be a great help.
I also changed the idler pulley thinking it might be the culprit

you used an autozone belt, that would be the first culprit. something like a timing belt you dont want to go cheap on. get an OEM belt

you change the timing belt tensioner as well?

Tensioned pulley spring free play?

First check the timing belt tensioner then check the alternator sounds like after two weeks the bolt wasn't tight and fell down a little

Changed the pulley, spring seems ok but I don't have a micrometer to check for sure. The part that I find the strangest is that when the spring is installed I can't adjust the tensioner at all its Luke the second pin keeps it from moving or something

i just bought a 5fse OEM timing belt from my local toyota dealership. it was only $37.

you might have to clap the tension pulley to the metal sheet separtater as tight as you can while you tighten the tension pulley bolt.