I have a 2000 accord vtec temp gauge is stuck at half dont move so not working and i have a bank 1 lean code help please

 

On the 00 to 02 accords the temp gauge signal comes from the ecu. the ecu gets the temp from a sensor located under the distributor. Have a look to see if the connector to the sensor is attached properly.
P0171:
1. check all connectors are plugged in properly (injectors,map,tps,temp,vtec,air temp,etc.), check/clean ground lugs on engine.
2. could be a vacuum leak, check all the vac hoses carefully
3. could be a plugged injector.
4. the up stream O2 sensor could be dying.
If 1. or 2. don't fix it get a obd2 dongle and install Torque on your phone, have a look at the long term fuel trim and O2 sensor voltage, then report back.
https://www.ebay.com/itm/USED-BAFX-E...jy4Q:rk:2:pf:0
https://torque-bhp.com/