I have been following your collective advise over the past couple of weeks in hopes of getting my 951 to run a little better. After the belts and waterpump, I've resealed my throttle body, corrected a problems with my TPS (lid blowing off), and just yesterday found vacuum leaks in the temp switch and the BOV.
The BOV SHOULD hold a vacuum at the small fitting at the top, right?. Mine doesn't so I'm thinking I need a new one, please confirm.

Second, I'm satisfied that my 02 sensor is working (what a pain to tap into that circuit) , at least it is active and seems to generally be outputting correct voltage levels. But in an acceleration run, I notice that right about the time I reach 14 lbs of boost, I can feel a definate drop in power with a stumbling/missing. Its like a switch has been thrown. A quick look at my O2 voltage in this scenario has it high ~.85 vdc (rich). If I let off of the throttle just a tiny bit, the boost drops and the power comes right back up.

Would be interested in your suggestions for a BOV and for my stumbing under boost problem. Cheers...Bruce

 

Oh, forgot to mention that I have plugged the vacuum control line for the BOV.

 

Get a new BOV, then see if problem still exist.

 

My first guess, based on personal experience, is that you have a vacuum leak.
Remove the airbox and AFM, find a way to plug the J-boot opening and air feed source (2"npt pipe cap w/ air-fitting) and pressurize with about 10psi and listen for leaks. Replace offending parts.
HTH
J