makijo wrote:what is a G Signal???
"G-Signal" is a somewhat miscellaneous error code that Mazda assigned, meaning it could be something as easy as a dirty Cam Angle Sensor (CAS) or as serious as a fried ECU.
I've noticed a lot of the early cars throw that code sporadically, but it doesn't seem to affect the engine's performance.
Just as something else to throw into the mix, how's the engine timing? I just ask since the G-signal can be caused by the CAS, which is where you'd adjust timing.
Also, I'd agree with Ian to check the voltage on the oxygen sensor. They sometimes won't give an error code when they're going bad, but since it analyzes the exhaust, a malfunctioning one could tell the ECU to give the engine more fuel.