86 Sabb 900 MAF problem...

I just recentlly installed another used motor into my 900 and i have 1 problem. The car starts up fine and runs... but it seems to be running sluggish when the MAF is plugged in. So when i disconnected the MAF the car runs and idles normal. Anyone out there knows what can cause this problem? We also tried 2 other used MAF and one new MAF and it still runs sluggish. So anyone know where to look?