On my Zetec there was a hesitation of 1-2 seconds when stepping on accelerator. No CEL. Looking at MAF sensor, found that the filaments were coated with dust. Trip to Parstsource store yielded a can of electronics spray cleaner. The guy in the store actually knew what I was trying to clean, and this cleaner is the right one, that does not leave any residue. MAF sensor in Zetec is a "constant current device". Current passes through the filaments and keeps it at set temperature. More air->more current required to heat the wire. Dust - reduces the time to cool the wires by rushing air, creates lag. Filaments look shiny silver when clean, any brownish coating means decreased performance. Can not touch the filaments, these are fragile and will bend or break if touched. I sprayed the cleaner from the can with the spray nozzle installed from very close distance, but not touching. It cleaned the filaments in about 3 seconds. Lag - gone.
