Intermittent throttle cut, rough starts, P0102 / INPA Fault 41

[crx00]

I'm hoping someone has seen this before because I'm stumped.

My 2001 E46 M3 (6-speed) has an intermittent issue where the throttle will occasionally stop responding while accelerating, usually between 1000–2000 RPM. Pressing the gas does nothing, even if I floor it. The engine continues running smoothly, and if let go of the gas, and get back on the throttle, the throttle response immediately returns. I don't get any EML light.

I'm also getting an intermittent startup issue. Sometimes the car starts and immediately stalls, or it'll start with a "waoooh waoooh" idle surge between about 600–1200 RPM for several seconds before settling to a normal idle. It happens randomly on both cold and warm starts. I've also noticed the idle dips lower than it used to when the A/C compressor engages, but it always recovers.


video of startup: https://photos.app.goo.gl/VprxLt1SKRWrrH7J8

The only faults I've consistently seen are:

• P0102 (MAF Circuit Low Input)
• INPA Fault 41 - Luftmassenmesser 1 (MAF)

Things I've already checked/replaced:

• New Bosch MAF (official Bosch seller)
• New Pierburg Fuel pump
• New OEM Fuel pressure regulator
• New throttle boot
• Throttle actuator tested by a BMW specialist and reported to be good
• Reset DME and throttle adaptations
• 02 sensors good
• ignition coils good
• Front and rear TPS good
• ICV cleaned

Live data from INPA:

• Warm idle MAF around 22 kg/h
• Lambda integrators stay around 1.00 on both banks
• Charging voltage is normal

Has anyone experienced similar symptoms? I'm especially interested if it ended up being wiring, the accelerator pedal, DME, idle control valve, or something else.

Thanks in advance!

[simplem3]

Well everything that came to mind you've seemed to address. I recently had a similar issue. EML was intermittent and I thought i had replaced both top side TPSs but it turned out to be the TPS on the throttle body.

At a high-level:

It went from EML to engine light. I ended up with codes for throttle issues and misfire. Replaced coils and for a while no issues, but then i started having thottle issues again and then the engine light came on. EML never came back on, but Ibecause I had an extra new TPS laying around I replaced the throttle body sensor and havent had any issues since.