'92 burb is giving me fits

[J Lee]

I'm having a problem with my burb. it started last Saturday while driving if I let completely off the throttle and got back on it it would stumble and sputter but then pick back up. The more I drove the worse it got and finally left me on the side of the road. At that point it would turn over but wouldn't crank unless I held the throttle to the floor and would not keep running under load (in gear). I wound up getting a ride home on a friends rollback. I showed him what it was doing and he said sounded like a fuel pump so we changed that and the problem still persists. I checked the trouble codes with a jumper wire and got a code 15. This afternoon I attempted to drive it to town only to have the same problem occur. I did manage to limp it home two foot driving and keeping the rpm up around 1500-2000. The truck dosent have a tach so that is a SWAG. I also noticed on the way home the speedo was registering way faster than I was actually running. One last thing, when I do try to crank it and even if I get it to run it smells strongly of raw gas. Anyone have any ideas?

Jeff