air/fuel gauge problems

[calvo]

ok this is unusual my air fuel gauge stoped reading or would read very lean and little to no switching. was throughing codes for bank 1 snsr1 no activity, insuficant switching and bank 1 too lean, replaced O2 twice no change. car runing very rich. pulled O2 bank 1 covered in black stuff cleaned and asitched with bank 2 sensor did not hook up air/fuel gauge car ran great full switching on snap-on scanner hooked up gauge bank 1 stoped switching only reading .019 to 100mV un hook gauge back to normal. it seemes the a/f gauge was grounding the signal. has any one else had this problem? power and ground to gauge are good. and gauge is about 21/2 years old