The PCV glove test was one of the first things I did. It’s okay. The plastic cover below the rotor arm is there, it’s in good shape, and it was clean inside.

Both the cam and crank sensors have been replaced. Also, running a boost test at 0.3–0.4 bar while bypassing the TCV rules out any issues in ...

Today I installed the pump 0 580 454 168 and I can confirm it's a plug-and-play replacement.

​Unfortunately, it didn't solve my problem.

​I pulled out the spark plugs to check their condition after 1,000 kilometers, and out of desperation, I reduced the gap from 0.7 mm to 0.6 mm. That didn't help ...

​I managed to trace the exact succession history of how Bosch superseded these fuel pump part numbers over the years:

​0 580 453 420
0 580 464 138
0 580 453 447
0 580 454 168

​It looks like 0 580 454 168 is the current, active Bosch part number for a direct, plug-and-play pump insert with proper ...

0 580 454 168 looks quite interesting. Apparently it cross-references with fuel pumps used in the Volvo X70/P80 range.

I haven't found any reliable information on its actual flow rate yet, but the aftermarket replacements for this pump are rated with better flow than the 0 580 453 420.

Judging by ...

Maybe Hitachi 133359 is actually a good choice? It probably looks exactly like the original part 1:1. I'm just not sure if it's trustworthy? I'm not familiar with this brand.

Bosch 0 580 314 067? Would you recommend something else?

Guys, I think I have a lead. I'm not popping the champagne just yet, but it's a start.

I routed the vacuum line directly from the turbo compressor housing to the wastegate, bypassing the TCV. It built around 0.3–0.4 bar. 3rd gear, WOT. The MAF reading maxed out at 408 kg/h at 5000 RPM, but the car ...

My only idea left is some issue with the MAF wiring harness that is corrupting the readings. Possibly a bad ground.

Quoting Volvospeed.com user Midnight Caller:

"From the VOLVO bluebook it seems that MAF measurement should be up to 408kg/h which seems consistent with the Bosch HFM2. Also, if we multiply 255 with the 1.6 scaling factor in the M4.4 RAM scaling we also get 408."

This aligns perfectly with the ...

The car is completely stock, with a stock turbo.

According to this table, it already hits full boost at 3000 RPM, which matches what I see on the boost gauge connected to the manifold.

The TCV is a brand new Pierburg unit, and I actually checked if it was connected correctly for the fifth time ...