Been having a rough idle, power loss and sometime stalls intermittent issue. Never on cold start or continuous driving. I commute to work and back without issue. Only after 10+ min of stop and go traffic or multiple engine on/offs like running errands. Only happens at idle. Usually at a stoplight. Engine light comes on and idle gets really rough then sometimes stalls. Always goes into reduced power mode. Start it back up and it’s drivable.

I finally caught it on the scanner. Using a Foxwell i70BT. I am not able to upload the live data video? Happy to email it or if there’s a way to upload it. But basically at idle, desired is around 700-800psi, actual will drop to 230ish psi or sometimes hover around 500. As soon as I apply throttle the psi comes up the match desired. Shut the engine off, wait 10sec and start it back up and it runs fine. Only code is 2880 (high pressure system), sometime will also have a 2745 (Multiplicative mixture adaptation)

HPFP? Just weird it never happens on cold starts. On cold starts it gets to desired psi in 3-8 seconds.

Ive replaced the fuel filter, LPFP and the current pump it a rebuilt unit from the guy in Canada.

When I bought the car I needed a HPFP and hardly started after many tries. Because of this I never drove it far so not sure if this issue existed before replacing all the fuel components.

 

Both codes implicate a low fuel pressure problem, so the HPFP would be a strong candidate.

 

I agree, its just weird that it starts fine after sitting.

 

Mine [R57 base] developed almost exactly symptoms [without the fuel pressure readings] over the past couple days.
Threw a cyl 4 misfire code & is only really there at idle or very light throttle. Anything over 3k rpm & it's fine.

 

I would replace the fuel tank filter and the sender as well as the HPFP. I did the same for mine when it had these issues and progressively got worse over time to the point where it would no longer start.
After replacing it all it fired up without issue. Make sure the HPFP is OEM from FCPEuro or other trusted sellers. I went through 3 HPFP because I tried used and cheap alternatives, after that I bought one from FCPEuro and it actually worked.

 

Is the HPFP in the tank?
Apples to oranges, but my dad's Focus has a LPFP to feed to the engine, then a HPFP under the hood.

And, I'm not seeing any listing for a HPFP [for a 2010 base Cooper] on ECS, FCP or RealOEM
I do have a spare set of coils, so I may swap those in & See if anything changes. Or just swap the #4 to another spot & see if the misfire follows.