My 1997 850 non-turbo keeps coming back with a check engine light.
the code I read from my scanner is PO172- Fuel too rich.
I've looked at several of the other posts with this error code and it looks to be one of several problems:
Vacuum lose.
o2 sensor bad
MAP snesor bad

Can anyone narrow this one down?
I've found a leak on my purge canister vacuum line and have replaced it but the code still comes back.
Is there a step by step process I should go through?

Thanks for any help....

 

Any other vacuum leaks?

 

Most probable cause I would think would be the O2 sensor. When was the last time it was tuned up, especially the air filter changed?

 

My 1st & 2nd replieson the following post may help some:

https://volvoforums.com/m_48928/tm.htm


JPN

 

Not sure about any other vacuum leaks.
How do
I go about testing for leaks?

 

Just changed the air filter...less then a month ago.

 

tuned up the volvo this summer:
rotor
distr. cap
wires
spark plugs
air filter a month ago
found a vacuum leak on the evap...repaired.

 

With the car running spray around the vacuum lines and if the idle changes there is a leak.

 

i got same code and change the the mass air flow sensor bought at ebay for $ 65.00.
got rid of the cel but does not improve fuel consumption. I also changed the air filter.
any suggestions? can we use 87 octane? i bought this used volvo just last month.
We got 18 miles per gallon.