Hello my son has a 97 850 with a readable code of p0171. we have pulled the MAF sensor and cleaned it with the appropriate cleaner to no avail. is there anything that we can do before we start changing sensors. I have read that this could also be a problem with the downstream O2 sensor. Again if anyone has any advice on this it would be appreciated this car is new to the family and I have never had a Volvo before.

 

Start by inspecting for vacuum leaks - tubing, leaks around throttle body boots etc. Also check fuel pressure ranges.