I was curious a few weeks ago so I borrowed a friend's smoke tester machine and found something interesting. To preface, my car seems to run fine but the MAF measures less than it did about 7 months ago. So naturally my first thought was maybe a vacuum leak. So when I put the smoke tester into the front of my intake boot, nearly EVERY GASKET on the TPI was leaking smoke like a sieve!

Here's the interesting part, when I started the car and sprayed carb cleaner at the runners to find vacuum leaks, the car didn't idle up or rev no matter where I sprayed it. My number one question out of this: People who have boosted TPI manifolds, how did you prepare your intake for boost? Because what this tells me is when the engine is under vacuum, the gaskets don't leak because the vacuum pressure is pulling them together, but with positive pressure inside the manifold, say with the smoke machine or in a boosted use case, it blows air out of every mate surface that could possibly leak, including the TPS sensor and IAC module. Another question would be, could this be screwing with my WOT performance even though I'm NA or am I worrying for really no reason?