Vacuum Leak
 

I have an annoying vacuum leak on my 05 tC, and cannot find it for the life of me. It is getting significantly worse as the weather gets colder. It is affected by the throttle; as the throttle is increased, so is the intensity of the leak. Any thoughts?

Already replaced:
PCV Valve
Both PCV ventilation hoses

Also inspected the injector O-rings, but did not find anything determinant.

intake manifold?

I took a can of carb cleaner around the intake manifold, but did not get any change in rpm. However, I cannot remember if the engine had already warmed up. I may go at it again immediately after starting it up on a cold morning. Thanks for the reply.

I had the same problem a couple years ago (2008 tC) and found the leak at one of the vacuum switching valve hoses. See attached picture for exact location of leak.


This was very difficult to find because the split was on the underside of the tube. Finally got my mirror and VOILA!!!!


Hope this helps. Good Luck !!!

Wow. Awesome info, and great picture. I will definitely look over that valve and its hoses in the next two days. I appreciate it.

Mine split in the same hose as jkois....twice. Mine also threw an evaporative emissions small leak/gross leak code when this happened. I ended up just cutting off the hose just above the split, then reattaching what was left. If this is your issue, make sure you cut off the split part completely so the end is clean. Any left over part of the crack/split will just grow bigger over time.

Okay. Definitely a good place to start looking then. But where exactly is this fuel vapor feed line? Like relative to looking directly at the front of the motor? Just to get an idea.

Nvm. I have found it. I will update whether this is the culprit or not.

Same problem. S few days ago that hose split. I cut it down and put it back on.