In my 98 Saturn SW2, P0172, system too rich, was caused by a bad engine coolant temp sensor. This is a common failure in these vehicles.It's cheap and easy to replace, and worth trying. When you take it out, if it's the original, it will be cracked. The new ones are metal. It takes a 13mm deep socket.
p0172
Code P0172 means: System Too Rich
Trouble code P0172 means:System too rich (Bank 1)
Trouble code P0172 means:System too rich (Bank 1)
P0172 System too Rich (Bank 1)
Trouble code P0172 means:System too rich (Bank 1)
Trouble code P0172 means:System too rich (Bank 1)
Trouble code P0172 means: System too rich (Bank 1)
Trouble code P0172 means: System Too Rich (Bank 1)
Trouble code P0172 means: System Too Rich (Bank 1)
Trouble code P0172 means:System too rich (Bank 1)
Trouble code P0172 means: System Too Rich (Bank 1)