89 Suburban TBI issue

[willwinchforfoo]

I'm having trouble running down the cause of my TBI issue. 89 suburban TBI 350. New distributor with new guts (not rebuilt) new coil, new CTS, new fuel filter. Runs rough when cold and for appx 10-15 minutes after warm and then smooths out and runs perfect. Has a rare stumble while running down the highway after it smooths out. Where should I check next? No codes thrown or stored. It's odd to me that it smooths out long after it goes into closed loop mode and not at the transition from open to closed loop. I'm debating with myself on rebuilding the TBI next to rule out fuel pressure regulator. I have not checked fuel pressure yet.
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[willwinchforfoo]

I hear crickets

 

[bucket]

How is the injector spray pattern on a cold start? A fine mist is ideal, but realistically, most with some age on them have some amount of dribble and still run fine. A crappy spray pattern can cause rough running.

Does it seem to lack any power even when warmed up?

 

[willwinchforfoo]

Turned out to be leaking fuel pressure regulator, bad distributor ign module and bad plug. The plug was causing most of the issue. I always forget to check the easy stuff.