Starting/Acceleration Problem for '96 OLDS 88 Part 2

Let me be brief and clear:

Problems: When car sits between 30 mins and an hour, it struggles to start as if it was starving for gas. When I sit in idle for about 5 mins or so (waiting for someone for example), car tends to make little ticking noises around muffler area; then when switched to drive after idle, blue smoke is shot out. When trying to drive off hesitation, engine light flickers on and off until stuck on. Not sure if it's an "idiot light" or not.

Key things to know:
Tune-Up done last January
Fuel Filter is rusted out.
Gas Mileage is declining (can get 250 miles/gal. within city orginally; now around 200-225).

4 possibilities:
1. MAF sensor
2. O2 sensor
3. Fuel Injector Problem
4. Ignition Misfire

All I know is that it is fuel related. Any help would be greatly appreciated. Thanks!

Questions, what is the cel code, have youy checked fuel pressure when this happens?

I haven't checked the fuel pressure. I don't know where to go to get it checked out besides getting my car "diagnosed". Any places in mind?

Any repair shop has a fuel pressure gage, or buy one for about 55-60 dollars.

I called around and some places do daignostics and some don't. NAPA said they do theirs for $49.95. Does the gauge read by RPM? If that's the case, I'm assuming under a specific level, then something is obviously wrong and I'm hoping it's just the fuel filter and not the pump, O2 Sensor, or MAF.

Fp is regulated by enginevacuum/load.

OKay....I was actually going to get it tested today, but 20 mins later after going somewhere and it stalled on me and had to get a tow home. You know what else it might be?? The carburator. I'm hoping not both the fuel pump and the carburetor. Is there a carburetor test machine too?

OKay....I was actually going to get it tested today, but 20 mins later after going somewhere and it stalled on me and had to get a tow home. You know what else it might be?? The carburator. I'm hoping not both the fuel pump and the carburetor. Is there a carburetor test machine too? Sorry, no carburetor on your car, it is fuel injected (MPI). Did you check for spark when it stalled? Will it start after the engine cooled down? You have to check for spark & fuel when it don't start!

My engine wasn't overheating or anything like that, the temp was just fine. After I had my car towed home, I just let it sit for a couple hours, then started it and it was acting like it was about to struggle again, but actually it was fine. So it's definitely either the fuel pump or filter...it was driving as if it was starving for gas and needed a tune up (which I got last January). I didn't check for spark though.