Curious if you were ever able to resolve this?
I have a Mk5 GLI (EA888 CBFA) with the same EXACT symptoms. The surging RPMs, feeling like fuel doesn't cut, jerking while pulling away from a stop. One time on the way to work, I was able to drive it without even touching the throttle, the RPM's just went up by themselves and I shifted the gears. I've been battling the issue for about a year now & have not seen any other posts with symptoms that are so close to what mine is doing. One time on the way back from a long road trip; the car jerked hard while pulling onto the highway, went into limp mode & started profusely smoking (White smoke) out the exhaust. I ended up going through an entire tank of gasoline in about 20 miles (Had no cell coverage & was alone so couldn't just pull over). After I was able to get it back, replaced a 02 sensor (Got scorched by the excess fuel) & drained the oil (Found tons of gasoline was mixed in) & it drove 100% fine for about a month before starting it started acting up again.
Started happening after I had the motor out:
Southbend Clutch Kit, billet rear main seal, billet transmission mount
Full timing kit (OEM)
Water Pump with Aluminum internals
IE Highflow Downpipe
In attempt to fix the problem I have replaced:
HPFP (OEM)
Coils & Plugs (OEM)
PCV (OEM)
Turbo Inlet Coupler (OEM)
Codes Thrown:
Throttle codes: P2101, P0638, P0221
Fuel Codes: P0172, P2293, P12A1
Misfire Codes: P0300, P0304, P0303, P0302, P0301 (All Cylinders Misfiring)
Other Codes: P0420 (Due to High Flow Cat), P0507 P0101 (MAF Codes?)
Compression test came back good. Also tested the injectors and it indicated no leaking. Most of the time when these issues start, it's a hot day (Over 90 def F); obviously this could be coincidental but wanted to see if you have experienced the same thing.
I'm thinking at this point it has to be an ECU or wiring issue. I have a parasitic Draw which I can't seem to fix & have gone through 3 Batteries as a result. Was also thinking it could be the VVT actuator or valve; Just a hunch due to the jerking at low rpm and touching the throttle a smidge felling like I was planting it to the floor. Currently pulled apart in my driveway for a walnut blasting (Valves are badly coated except for cylinder 4) & I need to decide what else I should replace while I'm in there. Starting with injectors, high pressure fuel pressure sensor, & MAF; But thinking I may replace the intake manifold as well.