Help!
I apologize in advance for the long post- but i need help!

I've been working on this for quiet a while and am running out of options.

Some time ago my245 started getting harder and harder to start. fuel economy plummeted and it was suffering performance issues. Poor idle at stop lights and poor throttle response. But every now and again she would drive fine (accept for the hard starts- they continuously got worse.
With the Hard starts also came small little sputters. those sputters eventually became small backfires in the intake manifold and the hard starts became no starts.

Things I have done:
Replaced Fuel Filter
New Injector Seals
Jumped the Fuel pump relay.
- I can hear both pumps run, and same problem persists when attempting to start car while jumper in place

Checked the Cold start injector and thermo time switch
- both seem to operate in spec.

Cleaned the Flame trap
replaced timing belt.
cleaned the auxiliary air Valve.

I can get her to "run" at an idle if i spray wd-40 into one of the intake ports. the interesting part there is usually when you spray wd or starting fluid into an intake manifold, the RPM's will increase- mine will barely run.

Again, after cranking over and over, she'll fire off, but nearly immediately backfire out the intake manifold blowing the hose to the auxiliary airline off either the intake manifold or the Auxiliary air valve- some times both.

The Volvo really wants to run. and I really miss driving her. Please Help me diagnose this.