Map Sensor Reading

[Gamikatsu]

What should a MAP sensor read on live data at idle on a 97 blazer 4.3 vortec.... i'm searching for a really severe fuel economy issue (11.6 mpg) and the ONLY sensor that i can see not reading correctly (i think) is the map. it shows 10.6 HG... i'm not sure if that correlates to inches of vaccum or not... i don't know how it works with MAP.

Thanks.

 

[SAATR]

Connect a mechanical vacuum gauge to the engine and see how the two readings correlate. If the mechanical gauge says the same as the MAP output, then it's not a sensor issue but a vacuum leak or engine problem. If they differ greatly, replace the sensor. Another thing to do would be to get a barometer and see if the barometric pressure reading from the MAP is accurate. If that is false, then it's going to run poorly by thinking the air is less dense than it actually is. I would expect to see at least 16 to 17 inHg at idle.