timing and Backfiring Issuse.

[boe402u]

I have a 1990 chevy astro, 4.3, 144,000 miles and now it won’t stay running and backfires. It was running great then all of a sudden, it stuttered and wanted to stall. I accelerated then it backfired like a shotgun went off then stalled. When trying to start it, it keeps backfiring loud and when I do get it started, by squirting starting fluid in the TBI. It idles then, I press the gas and it backfires and stalls and don’t want to start again. I don't know if it can be electrical going to distributor or what.
I put a tune up on it with plugs, dist. cap, rotor a few weeks back and it was running great with no problems at all. Please help me if you can and let me know what and how to check things so I can get it running again. I volunteer coach baseball for kids and also mentor and need vehicle for that. I’m on a S.S. Disability budget and that’s why I’m trying to do it myself. I’m pretty handy in repairing but this one has me baffled.
Thank You!

[DeltaP]

Basically recheck your prior work,everything. Don't assume anything to be OK. Check the distributor to see if the base hold down clamp got loose throwing the base timing off. A loose or cracked dist cap or rotor can cause the same.