i have a 1998 v70 xc w/ 195k. engine runs fine but has fault code p0172 (too rich). i've found only one reference to this code in the forums which was triggered by a bad MAF. fuel economy seems normal but there is one glitch in how it runs. and i have seen this mentioned here. occasionally at idle the speed will drop then recover. it drops only for a split second. even on highway you can feel it happen. its like the ignition or fuel is shut off then instantly back on. the 172 code is the only one though. would like to sell this car but want to get this taken care of first.

is there any links to some more details or causes of the fault codes?

thanks