volvo s60t erratic idle

i have already had a diagnostic check it showed up the faulty maf it was replaced but my car is still doing the same did not show any vacume leak or etm problem would a faulty etm show in the diagnostic test i have added a fuel additive called BG 44K POWER ENHANCER do you think that it would help clean the etm and ignition system thanks he only replaced what the diagnostic test showed thanks

If the MAF was diagnosed and replaced and the problem still persists, then I would take it back to the shop that performed the work. Have you tried doing this?