ECM 1 Fuse keeps frying

89 Astro Van with the V6
180K on the clock.

I started it up the other day and it ran rough, barely idled.
After that, it would not start at all.
ECM 1 fuse was blown
Replaced fuse, and it started but ran rough, barely idled.
Fuse blew again.
Replaced fuse, ran motor, same symptoms.
No ECM/SES codes expect for 12 (normal)
Fuse blew again.

Bad ECM? (no code 55 indicating so)
Or is there a short between the ECM and the fuse block?

I'm tempting to replace the ECM, but don't want to drop $120.00 to find out my guess was wrong.

Also, is there a way to test the ECM once it's out of the vehicle?

Any thoughts?

Thanks.