451stroker

I built an LS1 from components and finally got it running. It seems to have an idle problem. I did a physical check to make sure that everything is plugged in correctly and attached. What I found was that the new MAP sensor I put in feels kind of loose in it's mount. Is this normal? I have an LS6 intake on the engine. It almost feels like the nipple is broken off the sensor, but I don't think it is because I can see the top of it when I wiggle the sensor.

My other suspicion is that the used SLP Mass Airflow Sensor that I bought is malfunctioning. Can a MAF screw up the idle and make it erratic?

Thanks for any help or advise.