ACK!!!No Oil Pressure

This is kind of a strange one, while driving home from work yesterday, my 96 Lumina APV 3.4Lt died just like it ran out of gas. Since my fuel guage showed empty I proceeded to put gas in it. When I tried to restart it fired up but was backfiring and rapping really loud and only seemed to be firing on a few cylinders (it only ran for like 5 seconds) and when trying to restart it drained the battery. I ended up getting towed and put a charge on it to bring the battery back. I tried restarting with the same results, running rough and really noisy. I checked the fuel pressure and there was none so I then changed the fuel filter and got the fuel pressure back, the problem is now it runs with the oil light on and the engine is really loud so I know the oil pressure is low or none existant, I don't have a oil pressure guage to really see exactly where the pressure is at. I put a code reader on it with no codes at all. I'm afraid to keep the engine running for any length of time for fear I'll cook the engine. The engine only has 122,000 kms and wasn't making any unusual noises up to this point, it just seemed to run out of fuel. I dropped the oil pan to see if the oil pickup was clogged and it is clean. Is it possible that the pump may have lost it's prime when the engine was running so slow. I changed the oil and filter also since it was awhile since the last oi change. Any help is appreciated.

Thanks,
Allan

Pan down, pull some bearings out and take a look. If all is ok, put it back together and get a mechanical gage on it and see what the actual reading is, but the noise tells you something is up, if it is lifters it could have collapsed during extensive cranking, if it is in the lower end you should see something in the bearing inspection.

..mmm...broken camshafts have been reported in which case the oil pump does not run anymore and only a few cylinders fire with the remaining valves blocked randomy opened thus backfires....remove valve cover and check to see if all of the rockers still move when starting....the ones at front of the engine, that is alternator side, will, but may be the rear ones (transmission side) will not..
EDIT: by the way, check these threads, dramatically showing same symptoms ; they contain several links:
http://www.automotiveforums.com/vbulletin/showthread.php?t=402930 (check the last reply..one year later, in fact following this next thread where it should have been, logically))
http://www.automotiveforums.com/vbulletin/showthread.php?t=407222

Broken camshaft is very likely. These camshafts are hollow and are weaker by design(unfortunatly). Add to it like intake gasket leaks, poor maintenance(long oil change intervals) etc, and these things break more often than one would think.

It did indeed turn out to be a broken camshaft. Thanks for all your help. It is too much effort to repair so another APV ends up in the scrapyard.