Just passing along some info on this item.
My 89 started having a slight stumble on start up a few days ago, checked fuel pressure and it was low at 36psi. Also the pressure would drop to zero the instant the pump stopped running. This is what was causing the stumble.
There has been alot of problems with different brand name regulators from the big box stores, mostly complaints about not holding pressure. The main problem is the "button" that seals inside the regulator housing. The machine finish on the button is done poorly leaving deep scratches on the face of this button. I have seen many different brands with this condition.
I ordered a AC Delco 214-2156 and was surprised to see a much better machine finish. It wasn't perfect but better than the other brands I had looked at.
Even with the better finish I decided to polish it some myself. Spent about 45 min with 1500 grit then 2000 grit and got a really good smooth finish. Installed it,turned key on, pressure built to 42 psi instantly, and held there for 20 min before starting a slow decline. No more stumble!!

Thought this might help some one with a similar problem

Joel

Thanks for the tip, Joel.

Good tip, Joel. I replaced my regulator a few years back with a random brand (don't recall the name) and it ruptured within a year. I ended up replacing it with a regulator from TPIS. It's been running fine since then.