Originally Posted by
Caddyshack
If the fuel pressure regulator was failing or set wrong then the pump could keep running ask it would be opening lower and running fuel back to the tank which in theory could cause an issue....I guess it would run lean? If you can swap out the pressure reg then it is one less thing to worry about but more expense....that or fit a gauge to see what it is doing?
The ECU determines the prime duration, which can vary with temperature, as such I would look toward the CTS, which would also cause running issues.
Martin