Posted similar posting in alt.autos.pontiac.
My '91 Grand Am (2.5L 103k miles )has error code 45 - rich exhaust, low gas
milage (17mpg) and overheats quickly.
Expected the Coolant Temp Sensor, but this seems to work fine after testing.
I blame to much gas in the cylinders for all my problems. Is this right? And
what are possible causes for this??