need help - any suggestions to repair 96 LHS 3.5 so I can pass emission test. Rebuilt engine/trans about 10k miles ago. Has been running great- no codes, no problems. Last week cel came on for first time - Code P0171 (bank 1 lean) and noticed smell from exhaust like rich mixture in cat converter, checked for vacuum leak (had to replace intake gasket prior to rebuild due to random misfire / cyl 5 misfire). Could not find leak by checking hoses and spraying carb cleaner on intake. OBDII Reader said Bank 1 O2 sensor was low voltage - changed O2 sensor - No change. ST fuel trim at idle for bank 1: -19, ST Fuel trim for bank 2 : -4, Fuel trims get closer when you run rpms up sitting still - I think this suggests vac leak, but not sure where. Checked Fuel pressure -40 psi at idle, 48 psi with no vacuum to pressure regulator. idles smooth - confirmed firing on cylinders 1, 3 and 5 by briefly pulling plug wires. I suspect intake again but don't want to go through replacment to find out it is something else. Any help or suggestions on further diagnosis would be appreciated.
Thanks ahead for your assistance.

 

Just wanted to say thanks to Kevin and post a hopeful outcome. I disconnected the battery to reset the computer after listing the post. I have now test drove it and the fuel trims look correct. I am going to drive it a while and see if the code shows up again. Thanks