i pull about (or use to) 16-17lb/s of vaccum. my idle is sometimes stumbly and recently the Check engine light came one. I checked the code and it was 17. So i decided to replace the o2 sensor today. Well the way the DP sits the only easy way to change the o2 sensor is to pull the Y-pipe. So i figured no prob, That will give me a chance to fix a boost leak i was having @the second turbo. SO i pulled everything off and replace the gaskets between the turbo and y pipe. i made sure i hooked every single hose back up and tightened down the bolts. Started up the car and let it warm up. Took it out for a drive and now i only pull 14lb's of vaccum.

Now my boost pattern in first is 10/5/11 Second is 10-13-8 till redline.. 3rd is the same.. I pulled everything back off again.... Checked and triple checked my vaccum lines... no prob found. Also when i would drive the car around the pressure tank would vent pressure if i pulled the vaccum line off the nipple. It no longer does. I checked my check valves and all are operational and pointed in the right way. I checked the Rats nest (without pulling UIM) and i could see no signs of a broken solenoid or a host that popped off. Im starting to think that a solenoid is bad/stuck open thus disturbing the vaccum. Im to the point where im just going to go NS and say the hell with this Seq sheit. Anyone got any idea's on what this could be? Anyone local wanna help me with the NS converstion

Mods are listed in sig

 

Hi, this sounds familiar I was getting similar boost patterns, I put it down to old vac lines and dodgy o2 sensor too but I've decided to go the whole hog and go single to cut all the crap. Looking at your mods list though , what control are you using and have you compensated for the extra air in and out on the fuel front? I dont mean to sound a dick when I say that btw.

 

Im on the stock ECU for now. Next thing i do is PFC. Either that or a high speed run into a wall :T