Whats the scan look like? I wouldn't think the ICM or crank sensor would cause a 171 but the stalling seems odd. I would look into the placement of that maf, see if you can notice uneven-ness in what the maf is reading during a scan. I would put the maf next to the tb, then trim some off the 45 elbow on the filter side until things fit. You wouldn't want to trim much off near the maf because the 45 so close might skew readings.