So I'm very frustrated because my car just started to Idle after my mechanic did alot of work on it. He replaced the O2 sensors, the air control valve,the leak in the exhaust, and a new catalytic. So I drove it for about 14 miles and when I parked it, my car started to idle. I honestly don't know what to do anymore. I've put in so much money into it more than the worth of the car. Please HELP!

 

I replied to your post under Shuddering / Rough Idle, but reading the above, I'm confused.
You didn't tell us how it idles, rough/smooth, key in/out...

 

When it's on parked and neutral it goes from 750rmps to alittle over 1000 rpms.

 

sounds like the IAC valve or some vacuum leak. a lot of the time people replace these without putting the seal associated with them on properly and get a leak.

About investing more money than the car is worth; as long as you're not going to the dealer and spending out the nose for repairs, don't focus on that too much. With age, everything requires a little maintenance, some more than others granted, but they all will need it.

if you want to feel better about spending money: miles and time. Those two things cost money if you were to get into another car...which if you are still driving your TL, will be considerably less...saving you money in the end.

Keep driving it and spend your money on other things that will leave a greater impact on life; like time with others, chicken sandwiches, and possibly some left over for retirement