I always recommend running the turbos on Premium gas (91 and up). You are likely to burn a valve on regular gas. Worth running a tank of premium gas and injector cleaner and see if that helps. Has the car been sitting for any time? A stage 0 might be worth it and check if the flame trap is clean if ...

Yes, just stretch a glove over the oil fill and see if she sucks or blows. Obviously if it becomes a balloon, then the pcv should be fully serviced.

Do they really require such an antique at this point to pass emissions? Most states I know exempt anything over 25years old.

Wasn't a high HC a sign of badly worn rings? But maybe a PCV problem would cause high HC as well.
Oh, and check if you have a vacum leak. A GM 4 banger I owned had a high CO because of a tiny leak in the intake manifold gasket.

Sounds like a vacuum leak. What part of Denver are you in?

Did you check under the hood? Volvo used to have a sticker on the hood with the vacuum layout.

There are thumbnail pictures that you can expand on this thread from Volvo Forums website:

https://volvoforums.com/forum/volvo-850 ... ion-68636/

Neil.

One more thing: if you are not getting full boost, you might have a badly worn turbo, split intercooler hoses (check carefully, they might look okay if not boosting) or a shot intercooler. Usually it's the hoses, but I had a badly worn turbo in my 94 and you could smell the overly rich exhaust gase...

Note that red in Matt’s diagram doesn’t match the red on the Volvo diagram. Mark them with tape on your car before you pull them off

Tips from my side: Always record your fuel consumption. I know it is some work, but it pays off. Note displayed values can be incorrect, I always note distance and fuel consumed. If you are using excessive fuel then it is not running right. I was able to catch and diagnose some problems early becaus...

Honestly its not that expensive to buy like 10ft of each vacuum hose size and then replace all the hoses you can find one at a time. You can get some pretty nice high quality silicone hoses on ipd website or even amazon.

Only clean the MAF with MAF cleaner and don't soak it. I use an old toothbrush with MAF cleaner to clean the plastic mesh guard and a soft cloth for the rest then let it sit and drain out and residue.

Good luck!

Neil.