[scicala]

To convert to a carburetor will be quite ivolved, work and money wise. You will need a a pre- EFI distributor along with a carburetor and manifold. You'll also have to take the ECM out of the picture and eliminate the high pressure fuel pump and use an electric pump with regulator to get the correct pressure for a carburetor. Among other things I'm sure.
Just my opinion, but it's best to repair the problem with your current set up. There should be a garage around that can pull codes from an OBD I system.
There is a way to get codes without a scan tool, but I forgot how to hook it up. It involves using an analog volt meter and counting the number of times the needle sweeps the scale. Sorry I can't remember the details.
Also, might try checking the fuel pressure at the shrader valve on the fuel rail, or checking out the MAP sensor system. I have seen the vacuum line to the MAP sensor plugged with carbon before, where it attaches to the intake manifold.

Sal