strange vaccum issue....

[CDQICKGT]

alright car is a blown 04 GT with stock bosch bypass aon a vortech. problem is couple months ago i noticed i lost 10inhg of vacuum, then the other day i lost all vacuum. now the car surges at idle has a hesitation when taking off and dies when i stop. took it to ford for the smoke test but no leaks were found. also pulled the hose and pcv and found no noticable vaccum on either side of the valve. please help as this is my daily driver!!! thanks

 

[2000GTHRSE]

Check you IAC. I was having somewhat the same problems as your having in my 00GT..."not blown". I would be coming to a stop and my cars idle would drop significantly and somtimes even die! I replaced the IAC and problem fixed. But most idle issues are cause by a old IAC. Most people i talk to say it should be replaced every 65k or 70k miles. Another thing to maybe try is a compression test, yes a little extreme but could answer alot of questions. Just a suggestion

 

[phoenix99]

if you problem is not already solved, you can try to clean your IAC before

remove it, take extreme care to not break the paper gasket, fill the 2 holes with brake cleaner or carb cleaner or something similar, do it maybe 5-6 times, you should see all the dirt and crap is removed after, wait maybe 15-20 min before reinstalling it (just to be sure everything is dry)

now you have a cleaned iac

I,ve fixed mine this way

 

[CDQICKGT]

did that but issue is still there. i tore the dash out and check all the vacuum lines, they were fine. i did not that if i turn the a/c on the car idles fine. turn it off and idle goes to ****.wtf...

 

[CDQICKGT]

found the leak. turned out to be a melted vac line to the a/c! going back to ford today to get my $$$ back for the smoke test they "said" they did! thanks for the replies.