what could it be????

[yunior]

OK guys I'm back finally installed my gauges and my boost controller changed my sparkplugs to ngk bpr7es and properly gapped them between .7-.8 mm when I changed the spark plugs the stuttering seemed to stop but my greddy e01 (boost controller) and my boost control gauge have a reading of -7.5 psi when I turn on the car, when I get on it the most it goes up to is 10 psi and in normal driving its about -6.5 unless I'm accelerating, I have the stock settings on my SAFCII, and no adjustments have been made to the boost controller (meaning have not increased the boost on it) I have not done a boost leak test due to all the rain in fl now but would like to know what could be causing this problem how to fix what should I check for or any input that would assist me with the issue I'm having any input would be greatly appreciated thanks WTF

 

[v2ner]

that's the vacuum. it's normal.

 

[91gsxboosted]

that's the vacuum. it's normal.

It is not quite normal, that is a pretty low vacuum 6.5-7.5 psi. It should be near 16. Check your vacuum lines. Do you have the vacuum lines hooked up right?
-Joey

 

[91gsxboosted]

Also, without the boost controller turned up, it should only run about 10 psi.

 

[MrBoxx]

Vacuum is measured in in/Hg, not psi. But I agree, that does seem low for idle and cruising. Where did you tap in for the gauge?

 

[bird man]

i have a greddy unit and the vac only reads to 9.9
if you are in the 6 or 7 range you might have a leak or the line might be tweaked also.