FUEL CUT FSI

[Cmleclair2]

So my 2008 FSI has been experiencing a fuel cut. It runs perfectly fine upon starting some mornings but after driving for around 15 minutes cuts out and is VERY slow. I’ve replaced the low pressure fuel regulator and the fuel filter but the problem is still there. I also removed the HPFP to check the cam follower, it has a few small scratches but doesn’t look bad at all. I don’t know what to try next I’m thinking the the injectors, fuel pump control module, or possibly the whole pump. Someone lmk where I should start please.

[Cmleclair2]

It also is showing p0100 on the DTC but doesn’t make the check engine light go on for days after being cleared and driven. When it does come up the codes I get are p0171 and p2539.

[DBXdarkangel]

Could be Low Pressure Fuel System Sensor at the HPFP or the pump itself.

[Cmleclair2]

Thanks @DBXdarkangel I replaced the low pressure fuel sensor first so it’s not that. Next step is replacing the whole hpfp in your opinion?

[DBXdarkangel]

I'm no expert at all lol. I did a quick check on your fault codes and it suggests it's the HPFP or the sensor on top of it. It's defiantly a fuel starvation issue.

[DBXdarkangel]

P0100 - Mass Airflow Supply voltage intermittent

P2539 - Low Pressure Fuel sensor G410 (Open Circuit)

p0171 could be a vacum hose leak around the brake vacuum pump area.

[pudding]

Borrowing or buying VCDS along with a mechanical fuel pressure testing rig is a good idea, just to confirm it's actually a drop in fuel pressure and not a sensor lying.