Loss of power/fuel problems?

Loss of power -- Help!

Hi everyone,

I'm having some problems with the '89. About a week ago, the engine lost a lot of power, struggled to stay at 55 on the highway. It didn't seem to miss, there just wasn't anything there when I would push down the gas.

I changed the fuel filter thinking it may have been clogged and it was worse afterwards. The thing can't hold an idle and will only make it up to about 1000rpm at WOT. I double-checked the fuel filter and it's in the right way.

Any ideas or suggestion on what to check/change next?

Edit: Update below...

nope, check engine light is not on. I forgot to mention, though, that i did pull codes the other day and came up with 52 and 84. One is EGR-related (don't have my manual in front of me) and the other is power steering pressure switch open, iirc. I don't think either one is new (i know the power steering one has been there a while and i believe the egr code). also, i've changed the spark plugs, wires, rotor and dist. cap recently.

Ok, I was just out checking some more stuff:
The compression is about an even 160 across all cylinders.
The timing belt is lined up.
The vacuum stutters from 0 to about 5 (that doesn't seem right)

The engine still just putters and eventually just dies. Any ideas on what I should be looking at? Would the EGR thing be causing problems like this?

All of this started one night after I filled up the tank (at Jewel...I know!). It started running real bad (no power) later that night. I changed the fuel filter and that made it worse.

I'm kind of at a loss here. I'd appreciate any help or suggestions!