Idle Stability/Vacuum WTF????, Little insight here please Options

[bsamps4]

]Check out this video. My idle bumps just like the vacuum between 550-700rpms. It does this after the car has fully warmed up. Cold start the vacuum and idle hold firm until the engine gets up to operational temperature.

Things I\'ve done:
full boost leak test, and repaired the leaks I found.
smoke test, and repaired the leaks I found.

My question?....what else could cause this? Sticking IACV maybe????

oh yea...it\'s a 3rd gen 3sgte. Fully built...etc...most of you are probably familiar with my build. If not it\'s in the my project section.

http://s1190.beta.photobucket.com/user/bsa...403873.mp4.html





This post has been edited by bsamps4: Nov 12, 2012 - 7:18 PM

[enderswift]

Check the map sensor. My idle went to crap after I accidentally cracked the hose nipple. A little jb weld and the problem was fixed. If I remember correctly you have an FCD wired into it. I'd check that too.

It would explain why this only appears when your car is warmed up (it enters closed loop). Plus your guage is showing 20inhg, which is the same vacuum I get. So a leak isn't very likely.

Also it would take a lot for both bolts to loosen on the distributor, not to mention for it to then vibrate out of alignment without some kind of noticeable oil leak. However crazier things have happened so checking cant hurt

This post has been edited by enderswift: Nov 14, 2012 - 11:05 PM