Hey guys, I am an owner of lots of Volvos in the past 20 years, but almost all were red block rear wheel drives.

I bought this '94 850 after a college student had put a head gasket on it and never got it running again.

I found plenty of reasons for poor performance but now I am getting stumped.

So far I have:
Changed from dual tip Bosch plugs to normal plats
Put in a fuel filter
Fixed the intake leak from missing bolts
Replaced the oil separator (it was broken to pieces)
Changed the oil (it kept backfiring like it had gas in oil)
Reset the timing belt, (it was off by one notch on the bottom)
Swapped the cap, plug wires, injectors and fuel pressure regulator (used)

Now the warmer the day (I am in N Colorado) the better it starts and runs for up to 30 seconds. On a cold day it only runs for 3 seconds

The fuel pressure is 35-39 psi
Compression was 125-135 (Before I reset the valve timing)
The ignition fires consistantly
and the fuel injectors sound fine even as it dies.

So. . . could it be a plugged cat?
What about the set of butterflys in the intake? What is that all about?
What else could cause a brief run on this car?

Thanks for any ideas,
Stumped in Fort Collins.