I have a 01 S40 w/ 150K and the check engine light came on. Codes state bad MAF, oxygen sensor, misfire on 1 and 4. The vacuum nipple was broken and I fixed that and still throwing the codes. Today I'm replacing the plugs and MAF, hopefully this does it. No codes regarding turbo, but when I accelerate the turbo is definitely louder (whooshing) and if I mash the gas the cars acceleration is HORRIBLE. Do you think the MAF and plugs will do the trick?

 

That very well could do it. I am puzzled why the turbo would be loud though. Are there any cracks or openings in the plumbing?
Stan

 

Did plugs, and I noticed the hose goin to the intercooler is broke. stretched the hose a bit and clamped it and the car runs fine, but the hose came back off. Going to Volvo in the morning to order the hose.