Listen to the tech, start with the MAF. Its real easy to get at and if he says it will not pop up codes, he should know. I have an 02 XC70. I just had a #1 coil go, probably partly my own fault because I let the plugs go way past their service life. Changed all the plugs, changed the one bad coil (which did pop up a code for misfire on #1 cyl) and itruns as good as ever. I pulled the MAF out but it was almost like knew so I left it alone. Mech buddy of mine said to clean them with rubbing alcohol, don't use brake cleaner.
Good luck, I'm as cheap as you and hate to pay someone else to do something I can fix!