Question Hi Patrick,i recently checked my 1999 S70 2.4L
volvo with a diagnostic tool that i borrowed
from a friend. The code that was in memory
was P-0171 (bank 1), my engine light is on most
of the time, at the rare occasion it will dissaper for a day.Also on rare occasion the
engine RPM varies up and down at idle and for some reason it comes back to normal after a few
seconds.Can you let me know if there is something that i can do myself to solve this issue.
Thank you in advance for taking the time to
evaluate my request. Claude Zambito
AnswerHello Claude, well to start,volvos abhors a vacuum leak.There a couple of places we need to check. First is at the intake manifold,do this when the engine is cool.look for a small "elbow" shaped hose, you may need a light ,its to the right of the thermostat housing replace it if leaking.The other is by thr air filter housing.The code points to the front O2 sensor sending a report to the computer of too lean ,too much oxygen in exhaust. When the system can't adjust for the condition anymore,on goes the CEL.As for the rpm flux the throttle body is the most likely source.We cleand them every 30-60 miles.spray clean with nothing stronger than a toothbrush,your old one will work. good luck and good hunting ! my betty ann drives a 2K and we love it may you be happy too One other note,o2 sensor do get old and fail,a decent shop can find out.
