Car was running fine, parked for a week or so and now dies immediately after start (doesn't stop like it's low on fuel, stops like if I were to turn the ignition to off). No amount of throttle changes this behavior. I did some Internet research and found that disconnecting the MAF sensor might lead me to the cause if it runs after disconnect. Exact same behavior when disconnected. While in the engine bay I found that if I disconnected the Boost Pressure Solenoid, it started up and ran (idle was a little high, but seems to run okay). The fact it's running when that solenoid is disconnected leads me to believe it's not (at least entirely) a fuel delivery issue.
Would you expect that the solenoid itself is the issue, or does that lead you to expect it's some other issue.
Some background history that MIGHT be helpful.
Radiator cracked sometime last year (saw low coolant light and stopped before engine got hot), finally got it replaced in Jan or Feb. Took for a test drive and was running fine, then stalled on us right as we left the neighborhood. (Threw a fuel delivery code, but only once, and I didn't take a pic. Didn't show in history or active codes)
Would not start. If it did start, would die shortly after (felt and seemed like fuel delivery issues, with a sputter stop). Let it sit a few minutes, and then was able to drive it home without issue. Have since driven it far and at freeway speeds without issues.
Car shows 2 engine codes, will provide images in comments.
P0140
P0141
Stored codes
P0036
P0140
P0141
None of these are NEW codes, it was running "fine" with them.
Here's the part from O'Reilly's
https://www.oreillyauto.com/detail/c/dorman-oe-solutions/dorman-oe-solutions-turbocharger-boost-solenoid/doe0/667107/v/a/18039/automotive-car-2004-volvo-v70?q=boost+pressure+solenoid&pos=0
Interesting, a vacuum solenoid.
I'd guess it's defective if removing it resolves issues. When you remove it, do you cap the lines?
Places like autozone should have a vacuum pump to test it. It's probably a simple switch that closes or opens with vacuum.
So I got some new vacuum hose, and ordered a new solenoid. The solenoid won't get in until Tuesday, so tried the old one with 2 of the hoses replaced (can't find the far end of the third).
Had a bad start at first, then the next start it ran so I rejoiced thinking it was just a bad vacuum hose. Moved the car out so I could jack it up and look underneath to fix the O2 sensor 😭. After finding what I found in the other reply, I tried starting the car again to park it, but it keeps dying like before. I'm leaning more towards a fuel delivery issue, because a couple of the attempts seemed like it was out of gas. Unfortunately I have the steel gas tank, so the fuel filter is internal 🙄.
By disconnect, all I did was unplug the electric, left the component in place.