Rough idle and stalling
 

I've got a 2000 ls that is idling rough and has a delayed acceleration and it has a P0172? Rich stft bank on code. So far I've cleaned and tested the maf, new air filter, cleaned throttle body, tested the iac, tps sensors, checked for air leaks between maf and throttle body. I have a scanner that does live data and tthe fuel trims are really far apart at idle stft=3.8 ltft=-14.8. if anybody can give me suggestions on where to look next it would be greatly appreciated.

Try another MAF.

Well with all the stuff you have done I am thinking that you have a Vacuum leak some place.
This car may have the 3400V6 and I have a Pontiac that has the same motor. Rough idle and same symptoms.
So awhile back after the shops all check this problem out and couldn't find anything.
I was checking the Vac lines and I found one on the left side of the engine near the Power steering.
It's about a 3/8 " tube or larger and was covered by a rubber foam hose to protect it this had a big crack in it. I removed it and found the vac hose inside and was disconnected. I reconnected it and fixed it with tape to seal it.
No more rough idle.
This may not be the same one that is on your engine.
But you might want to check those Vac lines.
Hope it helps.

Thanks drivernumber3 I guess I'll be vacuum leak hunting this morning! I Gotta stumble upon a solution eventually right?