Air intake connector
 

Not sure what its called but( it is a rubber connector between the air filter housing and the back part of the housing into the intake manifold...Has had a rip inrunning it for about 5 years. all of a sudden it started running terrible( My 91 LS400 doesnt feature Limp Mode I think) Mechanic says it the rubber connector Any Thoughts Please

If this is what you are talking about you are in LUCK ! It looks like Amazon sells it for $11.50 w/ FREE shipping. It's an off name brand but the other option is at least $70 from a dealer... Hopefully your problem is just this simple but it may be something else since this tear has been there for 5 years.
Lexus calls it an Air Cleaner Hose 17881-50010

https://cimg5.ibsrv.net/gimg/www.clu...c2308f3b03.jpg

I was able to find one in a pinch from a V6 2002-2006 Camry/ES300/ES330. Cost was about $38 at the Toyota Dealer.

http://i145.photobucket.com/albums/r...u.jpg~original

http://i145.photobucket.com/albums/r...d.jpg~original