1989 Volvo 740 I don't know!

I have a 1989 Volvo 740 GLE Wagon with the overhead cam. 2 months ago, I ran out of gas. A wek later, the car acts like it;s running out of gas for 2 minutes, then dies. I start it and drivr off fine. A week later, the same thing happens. A wekk after that, it deos the same thing but I can't get it started. Try for 2 hours, then have it towed. The nest day, car is fine in park, I drive off, it chuggs in a pattern like I'm holding the gas for 2 seconds and then releasing for 2 second, and dies at stops while in drive. In park, runs like there's no problem. I replace the fuel filter, notyhing changes. I take it to the first volvo mechanic, he says his diagnostic machine says it's the computer. Take it to another volvo mechanic for a second opinion, he says it's the air mass sensor. I replace the air mass sensor, nothing changes accpet car won't turn over at all and I can't hear the fuel pump hum when I turn the key. A Vovlo dismanteler tells me it can be the computer, the crank sensor, the intank fuel pump, or the fuel pump. And that a bad computer could send a bad code saying the air mass sensor is bad. But to rule out the intank fuel pump and fuel pump, to connect direct current to them to see if they run. But I don;t know how to do that. Someone else said it might be the fuel relay, which I replaced 4 months ago, after buying parts I didn;t need to figuring everything out! So far, I have spent $500 just find out that it could b more parts, but no one can give me a definate answer. Help.