Originally Posted by Jordo!

That could very well be the problem. The MAF sensors do NOT like to be moved around -- they are VERY sensitive to airflow tumble.

Shouldn't be too hard to have some brackets made up to hold it in place. Alternatively, order the parts that were removed from Nissan (or see if the shop still has them lying around) and then have them cut to use as supports.

I'd take care of that before getting the tune -- the tune won't help if the ECU's getting erratic MAF signals.