CM871 fuel pressure delivery

[tree98]

Bubble test your injectors for starters

https://youtu.be/Wu_WN8BA-LA

Can you hear the fuel priming pump come on and run for 2 minutes when you turn the key on?

There's a check valve on the isfm to keep fuel from draining back, they do go bad.

You could monitor fuel pressure with insite while driving, maybe the pumps dropping out intermittently from a broken shaft or ??

What did the shops do to try to figure out the problem besides drive it around and wait for it to act up?