i had a problem with the map sensor causing an egr insufficient flow code. i checked it with a vacuum gauge and it read around 15 "Hg at idle. The map sensor should have anywhere between 1 to 1.5 volts at idle. I used a MODIS scanner to check the voltage and confirmed with a volt meter. Then compared that to the specs posted on ALLDATA that my shop uses. This is all on a completely stock engine though with no mods. Good luck!