[Genhero]

I drove the car for 3 hours back towards home on Sunday, parked the car for 30 minutes and started it back. The idle would sit at 800 sputter and misfire then jump up to 1500 then drop back down (almost like a camaro with a large cam on a cold start). If I revved it to 1500 in neutral it would almost shut off the engine when the RPMs fall.

It did this for a few minutes, I pulled the codes (check engine light wasn't even on yet) and shut it off. Let it sit for 10 minutes and turned it back on and it was fine. I cleared the codes and drove an hour and 10 minutes home and it hasn't done it again. I regret not logging the car since my tablet was already plugged into the JB4. It almost felt like there was a huge vacuum leak or like fuel was being cut/aerated.

29F4 / 29F5 (this is normal, DP Fix isn't adjusted enough yet)
2D2E Angle of throttle valve - intake pipe underpressure, correlation (this one came back on the drive home)
29CF Misfirings, cylinder 3
29D0 Misfirings, cylinder 4
0000 Unknown Fault
0000 Unknown Fault

I replaced all the vacuum lines with silicone hose last summer and they looked fine when I checked them on sunday. No couplers were off either.

Mods: Jb4 but it was disabled on map 0 to try to pass inspection soon, DPs, VRSF chargepipe, Tial BOV and DPFix.

Could this be a HPFP? I've never had a long start, it is always very quick and no limp mod or check engine lights.

Maintenance records show the dealership replaced all of the injectors and the previous owner gave me the old ones too. HPFP has never been replaced as far as I know. I replaced the spark plugs, water pump, thermostat and 1 coil pack last summer.