Hi,
I have a 98 non turbo v70 with about 150K miles. For the past 4 months it has been idling rough, hesitating, and stalling. My volvo shop has never been able to figure out what it was because the CEL wasn't on. They replaced the fuel pump relay, cleaned the fuel injection, and cleaned the throttle body to no avail. I have taken it to 3 different shops and no one could find the problem. The engine light came on last week and the code read PO171 bank running too lean MAF or VAF. I changed the MAF sensor and it hasn't changed anything. No one seems to know what VAF means. I have changed almost every hose related to air flow and it hasn't helped. Any ideas?

 

Hi, in my old 850-94 the air in take manifold gasket started leaking gradually more and more when the car was about 10 years old. in the beginning rough idling later ramping idle rpm. if spraying soap water around makes difference you have hit the leak. new gasket was 10euros only. there is also a vacum unit under the manifold controling the air intake route, something might leakinvisible there as well. I assume you have cleaned the idle air control valve as well.
br tapsa

 

I haven't. I'm not a mechanic. I've only done basic things like change my oil. I'm not sure where the manifold gasket is but I'll look it up and give it a try. I assume I spray it while its running? Instead of stalling now she has a hard time getting going once she's started. When i first crank her up, the service light comes on even though I just got the oil changed. If I drive off immediately, she wont go over about 5mph no matter how much gas I give her and then she'll suddenly speed up then drop back down. After doing that a few times, she runs OK and the service light turns off. I've found if I let her idle a while before taking off she runs no problem. The problem seems to be when I'm at about 1.5 RPM or below. If I keep her revved there for a minute in park, she evens out and runs fine.