Air intake tube assembly problems
 

I have a 2000 LS 400.. Had different lower part of engine put in car and used all other pieces from my engine for everything else..(bought car from an older lady ..original owner..said she did timing belt well she didn’t.. so it broke and took out that part of engine) so I got engine out of a wrecked lexus with 80,000 miles.. (not bad for a Lexus motor) anyways the shop that put engine back together cracked my air intake tube assembly.. and they tried to rig it.. Without telling me.. found out after the 60 day warranty was up.. of course! Cause check engine light came on so took to a different shop.. Long story short.. the car idles like crap.. has died on me quite a few times.. crappy gas mileage and now I go to fix that part and Lexus discontinued it! Help what and where can I find the part?