P0442 = Volvo Code EFI-612 Fuel Tank System Small Leak


P0445 = Volvo Code EFI-541 Canister Purge Valve Signal Low
results in poor performance, fuel odour, uneven idling

P0172 = Volvo Code EFI-231/EFI-232 Long term fuel trim at upper limit
results in high fuel consumption and poor performance.
this one seems related to the canister purge valve leakage.

Don't unplug the MAF while the key is in pos II or engine is running.
check for voltage of 0.1-0.2V between pins 2 & 4 at idle with MAF still plugged in.
Does the car idle better with the MAF unplugged?
Does cleaning MAF help? How about cleaning the connector contacts?
Can you borrow a MAF to try?

check grounding:
turn car off
wait 5 minutes
unplug MAF
check resistance between pin 1 and ground on MAF connector - should be 0 ohms
check resistance between pin 2 and ground on MAF connector - should be 0 ohms

check sensor signal:
ign to pos II
check voltage between pin 4 and ground - should be 0-1V


This fault also could be related to a bad fuel pulse damper (shiny disc thing attached to fuel rail) though I wouldn't think this would keep the car from starting.

P0121 = Volvo Code EFI-121 MAF signal too high
results in uneven idle and poor running


Also I would be replacing vac line like crazy - replace every vac line you can get your hands on.

This doesn't sound like a CPS but make sure the wire is routed away from the ign wires.
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1998 V70 AWD Turbo 195k+