High Idle -> Vacuum Leak?

ybstuk · 04-07-2008, 10:56 AM

'95 Mustang - 3.8 v6 - 115K miles. just purchased car. High idle - 2-3K rpms. replaced IAC valve, and tested MAF as per autozone's recommendations:
http://www.autozone.com/servlet/UiBr...3d801dd3cc.jsp

My voltage coming from my MAF was 1.75 volts - perfectly in range as to what it should be.

Cruise control doesn't work, nor does the heater/air cond selector (only blows out the defrost vents). If i had a vacuum leak, that might wipe out all those things. BUT, i do have good power brakes still. Anyone have any thoughts about this?really trying to get this high idle under control. If i had a vacuum leak, where could it possibly be? does anyone have a diagram showing the vacuum lines that i need to check? would a chiltons or haynes have this? any help is GREATLY appreciated! Thank you!

Bryan

92lxsleeper · 04-07-2008, 11:40 AM

if you suspect a vacumm leak, and ur hvac controls arent responding... check there first. the brakes on my cougar were not vacuum assisted and idk if the mustangs were the same or not. but even with a vacuum leak... unless there was alot of them.. or a BIG one, u should not be idleing at 2000-3000 rpms. maybe around 1000.... i'm thinking that your butterfly isn't closing all the way.. clean it out and oil it very well with a thick penetrating lube. that happened on my 2.3 stang coming home from work. and when you gain rpms, you lose vacuum, so in theory, it could affect with your hvac controls...

for the cruise control... either your fuses/relay is blown, or the control motor is shot, very common on fords for some reason.