Quote Originally Posted by Rich View Post
Before ordering any parts be sure that the hoses that feed the warmup regulator are all solid. No splits, no cracks? Use an inspection mirror to verify, assuming you can't smoke test them.

A very small split/leak in the hose at a tee leading to the rear fitting on the WUR was causing a stumble during cold acceleration on ours at one point a few years back. After spotting that split I replaced the hose. Solid ever since and still on the original WUR.
That won't impact the static pressure though, and his is too high when cold. Still a good thing to check if you have a car that falls on its face when cold.