i have just fitted a new o2 sensor and it still reads rich all the time apart from when you rev and let off, it drops back lean momenterily,

the chip is an AB stg 3 on a pectel board, (3 bar map, 803s) since i fitted it ( alog with the other bits and fuel pump, it has done this, but while its been in storage so it has not had a road run for about 18 months