Ok I NEED HELP

[canalguyopen]

Alright first let me say that I'm a little embarrassed to be asking this because I have worked on cars for 24 years but here goes....

The old lady has a 00 Alero 2.4 Vin T model and it had a surge at idle. I have been chasing it down for about a year now and have replaced way to many things to list here but all of the usual suspects. IAC, TPS, MAP ,fuel pump, CAT, Plugs, boots, coil, both O2 sensors, purge solenoid, all filters (fuel, air, etc) Just for good measure I installed a new battery, and some other things.
The surge is STILL there, not only that but after replacing the TPS last night the car will now stall at every red light and stop sign. It's been throwing the old 0440 code for about two weeks so I went with new fuel cap and purge solenoid. (not the charcoal box yet but looks like I will have to) So after all this work it runs worse than it did when she bought it used lol.
The surging is driving me nuts I don't for the life of me know what else it could be other than a vacuum leak but two solid garages have smoke tested and told me no everything's fine.

Obviously the surging is a bother but this stalling deal just started over night after replacing the tps. She said every time she came to a stop the car stalled. 6 times in 3 miles. I did nothing yesterday but unscrew the tps and screw on the new one. It was not stalling at all before this change.
Like I said I have been at this for over 20 years so I am a little embarrassed to say this but , help!