Hello! Had a really odd issue with my '98 V70 AWD. It has a B5442T engine in it, with 193K miles.

Experienced a stallout while braking at a traffic light the other day. Car would fire right back up, but would be idling rough, and then stall if I tried to gas it. Parked the car and let it sit for a few minutes, and when I turned it back on, it wasn't exhibiting the symptom. Later on, I drove home (30 min on the freeway), and it stalled right after I took my exit. Same issues as before. The strange part, is that out of the 10 or so stalls, no error codes, no check engine light.

With no codes to work with, didn't have a whole lot of options other than to throw parts at it. Cleaned the MAF sensor/housing, no fix. Just so happened to have a fuel filter for the car, installed that, no fix. Pump was priming and functioning, so I knew the pump itself was okay. Car's fuel pressure at the fuel rail was okay when the car was idling (unsure the pressure when exhibiting symptoms). I bought a MAF sensor and fuel pump relay, knowing the issue would be one of those two things. A couple MAF checks made me think it was faulty (unplugged it while car was exhibiting symptoms, no change to car's idle). After installing the new MAF though, no complete fix; car's iradic idle was fixed though; would still stall though. Installed new fuel pump relay, and et voila! Issue resolved. Prior to installing the relay I popped the housing off the old relay, and it looked fine. I've heard of these relays running hot as they age, and functioning very inefficiently, drawing incorrect currents and intermittently failing.

Hope this helps if you're experiencing similar symptoms with no check engine codes! Let me know if you need any clarifications.

 

Strange that you got no codes. Good to know about the relay. Thx.

 

my car had the same symptom as yours and I did almost avery thing you did but I also change temperature sensor. and now its worse than ever. I start the car and I have rough ideling until it stalls out. So I don't now what to do anymore.Im thinking of giving up, I spent enough money and time on it.

 

It's such a tricky symptom, because there are like 30 things it could be. Does it seem like your issue is fuel or air related? If you hit the throttle when it starts up, does that kill it? If so, likely fuel related.

 

On the '98 MYs and prior fuel starvation (typically caused by bad fuel pump relay, fuel pump, or fuel pressure regulator) will not set codes.