It finally happened... loss of performance.

I was taking my 740 TI from southern CT to upstate NY this last weekend. (Geez, it's almost Thursday already)!

The car was missing like crazy, spool up time was terrible. My sleeper morphed into a dog without any notice.

Here's what I have noticed:
At partial throttle/boost around 4,000 RPM I am a black smoke factory. gas mileage is like I'm driving a tank, so it has to be too rich. I made it to NY like this, where I bought new rotor, cap, and splurged for platnum plugs. (I looked at the fouled plugs before I bought new ones and figured platnum was the way to go to get home if this did not fix the issue.

It didn't. Checked timing and all hoses. even pulled the intercooler to check it for a possible leak. good news: not a lot of oil in the IC. I pulled all induction hoses. found the hose from the AMM to the inlet of the compressor hose, where the little "turbo bypass" (by the book's discription) from the oil seperator, had a fair oil trail that was not there before.

This leads me to think that I now am experiencing excessive blow by of the piston rings, causing crank pressure to carry a lot of oil over to the compressor inlet. This is a guess. I planned on doing a compression test when I got back. I have been too busy to get it done yet.

On the return trip, I adjusted the grainger valve down to about 4 psi, where I could at least use a little more throttle before it was spitting black smoke.

I am wondering, could a blown head gasket also cause excessive smoking? would it cause plugs to oil foul?

I still plan on doing a compression test to see where I am at.

I welcome all thoughts on a big loss of power, loss of avaliable throttle (before smoking) and excessive black smoke.

Thanks for helping me brainstorm!

Oil Eater (for real this time)