| This has happened to me twice over the years after plenum pulls. Both times it was due to plenum gasket or the plenum not being fully tightened down. Air leak was so large it doesn't make a sound because the air escapes so fast and from a large area. (large is a relative term, because simply unplugging the 1/4" recirculation hose from the rear of the balance tube is enough to cause the car to die at idle) With my issues, I could never "see" the problem with everything put together, and I too tried the boost leak test which seemed to pass. The only way I fixed the problem was to remove the plenum again, and then reassemble. One time it was obvious because I could see the gasket was fubared when I removed the plenum. Apparently had slid when I was putting things back together and gotten torn. The second time I had to re-pull the plenum, I could see nothing obviously wrong when it was removed. But when I reassembled it, I made sure the gasket was aligned using a pencil in the holes and carefully tightened each of the bolts again. The problem was gone. So by process of elimination I deduced it was an air leak that was caused because some section of the plenum wasn't tightened quite enough or that the gasket was slightly off.
|
