Plugging a leaky turbo -- please advise.
 

So, some background is in order.

I have a 1997 Volvo T5. It's got roughly 230,000 miles on it. The "Check Engine" light has been on for the past few months. Initially, there were two codes -- one for a slow O2 response and one for an inefficient catalytic converter.

I replaced the O2 sensor, but the check engine light didn't go off. I had it into a garage that tried two different sensors on it, but had no better luck. They ran a smoke test on the car, and discovered a massive vacuum leak in the Turbo. They can't tell me if the catalytic converter is bad or not because the engine is refusing to run that diagnostic.

Here's where my question starts.

My understanding is that there's a plate you can get and have installed on the car that will plug that hole by disabling a function that's only useful if you have the *manual* version of the car. (I am uncertain exactly what the function is, but my car is an automatic.)

I have to pass emissions testing soon, which means I need to get this part ordered -- I guess its made by Mitsubishi -- but does anyone here know if it's the right part? I'm looking at a hefty repair bill either way, but I'd much prefer to install a metal cap as opposed to installing a new Turbo or the repair kit from Volvo, which is apparently also quite expensive.

Any advice?

Bonus question: Anybody have any idea why my AC works erratically? It will kick on for 15-20 minutes, then kick off. I have to cycle the AC from off, leave it there 10 minutes or so, then turn it back on. Every garage I've taken it to said that the unit is working fine, but I'm wondering if the turbo vacuum leak could be screwing with the AC in some fashion. I'm not redlining the engine or gunning it -- this happens in ordinary city driving and on the freeway.

a/c clutch gap is too large, probably. Two way to fix it. Either take the shims out of the clutch to set the gap correct or shove zip ties thru the backside of the clutch to put it closer.