eglade
Active LVC Member
My Mark has recently developed a major vacuum leak in the intake valley area. It appears to be the manifold itself as a spray test and visual inspection reveals no leaks in the upper area of manifold or connections.
The leak is a solid, loud hiss but only affects driveability intermittently. It starts and runs fine and only occasionally exhibits a fluctuating idle. This condition does not last long and no trouble code is displayed. What puzzles me is that the leak would seem to be in the intake. If a large quantity of unmetered air were to enter, would'nt the computer sense the lean condition and go richer to compensate, thus throwing a check engine light ?
The leak is very loud, but not easily accessible. I'm getting ready to start pulling components for more access to leak area. I have only been able to do a quick driveway diagnosis and plan on diving in deeper when time permits. Any vacuum controlled solenoid or connections under the throttle body, runners or plenum area I should pay attention to ?
Anyone else have this problem?
Any assistance would be appreciated
The leak is a solid, loud hiss but only affects driveability intermittently. It starts and runs fine and only occasionally exhibits a fluctuating idle. This condition does not last long and no trouble code is displayed. What puzzles me is that the leak would seem to be in the intake. If a large quantity of unmetered air were to enter, would'nt the computer sense the lean condition and go richer to compensate, thus throwing a check engine light ?
The leak is very loud, but not easily accessible. I'm getting ready to start pulling components for more access to leak area. I have only been able to do a quick driveway diagnosis and plan on diving in deeper when time permits. Any vacuum controlled solenoid or connections under the throttle body, runners or plenum area I should pay attention to ?
Anyone else have this problem?
Any assistance would be appreciated