i bought an air fuel ratio gauge for my 280zxt and it marks lean when is parked with the engine running and when i press on the gas it goes up to the next light but stays on lean what are some issues it could be thanks

 

what does it read at full throttle? that is where it really matters. lean at idle is no biggie. plus unless its wideband, i wouldnt trust it much for exacting accuracy

 

Also remember that the 280ZX O2 sensor doesn't have a heating element, so you have to let it warm up before it will read accurately.