If the service number on your ECM is 1227227, it's a good chance that the ECM is the problem. 90-93 Lumina's ahad a high ECM failure rate, due in part to it being mounted under the hood and exposed to the elements.
(The above post was sent in from another member back a couple of years ago).
Fuel pressure should be 37-42psi. I believe. Thats the requirements for the 3.8. Someone may correct me here.
There also seemed to be a problem with the crank sensor located on the right rear at the transmission on these cars, however a full scan should reveal this problem.