I've got a 95 blazer 4.3W. I just replaced the spider, nut kit, crank sensor, cam sensor, Dist cap & rotor, plugs, coil. The SES light will come on and flash after about 30 seconds of running. I can shut it off with my scan tool but it comes back. The scanner is digimoto 3.6 on my laptop. It doesn't show a code but it shows the light is on.

I also encounterd another problem. I checked the compression, it was 150 - 160 on all 6, as long as I had the plugs out. The blazer wouldn't start after I installed the plugs. I had to hit it with a squirt of starting fluid.

I've got 247k on the beast. I did all this work because it died on me and wouldn't start about 6 months ago, never got around to fixing till now.

A flashing check engine light is a missfire.
With a no start with aid.
I would check fuel pressure on a cold start
Has to be up to par.
Even a couple of lbs low will give a no start cold.
Also low fuel pressure will sometime cause a missfire.
Post back fuel pressure readings.
MT

I've got 60 psi with key on 56 running.

That is good as long as it holds there after 20-30 minutes running.

Does it restart now after getting it going or do you have to aid it when cold start?

A flashing light is a missfire.
If light is on there should be codes.
Try to get codes and post back code no?
Try to find missing cylinder and work on that end.
Can you feel a miss?
Old style dist or new type flat top cap?
Good Ac delco plugs and cap and rotor?
Have you set dist/or timing?
MT