Sorry for not following up sooner.

LONGs are only available in PBP 2.5 and newer and for 18F parts only. LONGs might make this easier but should not be needed.

First off, do you have

DEFINE ADC_BITS 10
In your code?

Next I have a question about your senso to get started.
The sensor has an output from
0.66 to 3 volts ?
0 to 3.92Kpa ?