Hey guys, I have a few questions for those of you experienced in idle issues/vacuum leaks. To start the story off, a while ago I removed my charcoal canister, and all of the vacuum lines that went with it. The line from the gas tank I just have sitting open in the engine bay, since it doesn't seem to be causing any problems. Shortly after, I started getting a "progressive" vacuum leak, where the car will idle fine for a bit, and then I will start to lose vacuum. The gauge will slowly go up to ~15 inHg (19 is normal).

This problem has recently gotten worse, as the car no longer pulls 19 inHg at any time, and the idle is stumbling between 800 and 500. I also notice a big power loss down low (up to 2300rpm) and the car will jerk in gear when I am coasting along, or press the throttle when the revs are down. As for the vacuum lines, they are all pretty much new. I have checked all of the connections, and they are fine. The vacuum line at the top of the manifold right past the throttle body i have connected directly to my boost gauge, and the bottom one is open air.



This one goes directly to the EGR, and just sucks in air when the throttle is pressed, and was already pulling in unmetered air from the canister. It seems like I can hear a small leak coming from around the EGR, most likely from this box of sensors:



Does anyone know what these sensors go to, or maybe have had problems with them leaking? There is vacuum connected directly to them. I also have a cartech FMU tee'd into one of the lines coming off of the side of the manifold behind the throttle body, if that makes any difference, but I don't see why. Anyways, sorry for the long post, and a if you made it all the way through. Any thoughts or advice would be much appreciated! Thanks!


- Brad


Edit: Since disconnecting the canister, I had a high idle initially. I adjusted it using the screw on the IACV. I have tried correcting the vacuum problem by adjusting that screw some more, but it doesnt have any effect, aside from changing the idle speed.

 

first, put the vacuum lines back on the charcoal canister.

second, disconnect the EGR valve's vacuum hose at the EGR. see what that does. if it's puling vacuum while you're at idle, then the solenoid is bad. the solenoids are the brown and green guys in the picture. I forget whitch one goes where, but one of them will be bad.

 

Brown is EGR, green is power valve for the VI.

 

My car will jerk when its in gear when I am coasting along, even downhill. I don't get it.

 

see the valve functions : http://www.cardomain.com/memberpage/748507/1

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Well, today I tried re-connecting the canister. There was very little, if any change in my idle. I also checked the EGR, and everything seems to be working properly, the diaphragm is not sticking, nor is it pulling vacuum at idle. This weekend I'm going to try pulling the IACV and cleaning it, hopefully that will help. The idle sometime takes awhile to drop down to normal and on cold starts the rpms will jump to 2K for a split second, so maybe thats it. Right now the car isnt as bad as it was, the car will idle fine for around 30 seconds before it starts missing. I still have the power loss though, but it runs normally above 2K.