93 APV No Start

I have read through the posts but I haven't found my particular problem. I have a 93 Lumina APV 3.1L. It has sat for about a year but it has ran fine for the past month. I went to back out of the driveway and as soon as I put it in reverse it died and won't restart without starting fluid. Once I get it started I have to give it a little gas to keep it running. I put in a new fuel filter and pump. I have also swapped the IAC, TPS, coolant temp sensor, injector assembly, and MAP sensor from a 91 APV that I have for parts. The 91 ran fine, I just rolled it last winter. I took it (the 93) to a shop and they said the computer was bad. So I swapped computers (same serv. number) and I did put the 93 prom chip in the "new" one, but nothing has changed. I would appreciate any help on this. Thanks.

For anybody that wants to know, it was a bad spark plug wire.

Be sure to always give a good explanation of what the exact problem is. Its kinda hard to help over the internet allready, and its even harder to help if we dont know what the engine is doing when it does run.

Nevermind, its doin it again. It has to have starting fluid to start, and I have to give it a little gas to keep it running. If I don't, then it will run for about 30 seconds or so. It sounds like the engine slowly revs down until it dies.