scan tool map vacuum reading

[rammit11]

Hi, I was running a live data scan on my engine today and I have a question on what the value of hg. should be when on scan tool . I get a reading of 29.5 koeo and with the live data I see 10.5 with engine idling and does show a drop when revved, is this normal or should I be seeing more when running? I did a check on engine vacuum when I first started the engine at break in and was around 20".

[IH 392]

When I looked at my stock 4.0, '97, it showed about 12" with two different MAP sensors.