The MAP will indicate Millibar pressure. Don't expect it to be exact, or so accurate that you can figure altitude plus today's local barometric pressure. If the MAP(mass air pressure) and your MAF(mass air flow) are working, that is not your issue. MAP under WOT should max at 2300-2500mb, then drop to around 1900 for stock application. MAF should read 255-275 and go up to 850 at WOT.
Depending on the misfire, if it is a dropped shot, a regularly mis-firing injector or a stumbling would mean different things. White smoke when cold could be oil, fuel or water. How white? What does it smell like? Does it evaporate? Is it white only when cold? Is it blue smoke, really?
Have you run VCDS to check for codes? If not, you are shooting in the dark.
More information or it cannot be pinned down.