Possible head gasket but this is a HPT. I don't think it's going to fix itself under boost.

On a HPT, boost does not come on until about 3000 RPMs.

Just completed installing 4 subframe bushings and new spring seats with genuine Volvo parts. Its a pretty straightforward job for those contemplating it. I didn't document the spring seat install as it is a simple process. Subframe bushings should take 3 or 4 hours with hand tools, nothing special r...

U. have three P2 cars at about 200k. For heater cores I'm waiting for mine to show signs of failure. 06 S60R - This winter the heater was not as strong and on the coldest days it wasn't really sufficient. Presumably the core internals were somewhat/somehow clogged up from 190k miles and 20 years of ...

Try here: https://www.carparts.com/details/Volvo/S60/Behr/Heater_Core/2007/BEH15751003.html?TID=bngpla&origin=%7Badtype%7D&msclkid=462b8086a70b1095cdbae7355d72b28c&utm_source=bing&utm_medium=cpc&utm_campaign=BPM%20-%203PB%20-%20Catch%20All%20-%20Parts&utm_term=232526093490073...

Wipe insides of lower air vents on both sides with your finger. They get greasy the first thing when heater core starts showing age.

Date should be on the boot. It looks like a clock with a ring and arrow; arrow pointing to month and year is between the arrow.

06W11 on the top = 2006 week 11
06W22 also on the top = 2006 week 22.
The boots may have been replaced or the coils were not FIFO at the Bosch plant.

Coil on plugs, throttle body, VVT solenoids, brake booster check valve/vacuum pump switch, turbo control valve, boost absolute pressure sensor (located at the intercooler outlet), fuel pump control module (hard to reach near the front of the fuel tank on the passenger side), HVAC blower fan and resi...

Just do one. Technically you should reprogram the HVAC for the filter of choice , you can get away with moy]t doing this in the cool NE, you might not get good AC in Alabammy!

Jim warned me about this when I bought my P2 from him in 2014

I would say that you did the basics. Without investing into ton of diagnostic equipment, it would be hard to pinpoint anything. I woukd suggest to send to dealer and pay 1-2 h diag fee. It could be variety of the issues: low fuel pressure d/t leaky injector or backflow valve, problems with engine co...