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I've been struggling to solve an issue for several months now. I'm hoping someone here might be able to give me some ideas.

I have a 2012 Q5 3.2L with 100k miles. Maybe 6 months ago it started having intermittent starting issues. Sometimes (maybe 10-20% of the time) when I push the start button it will stumble/misfire for a few seconds, struggling to get over 800rpm and then stall. Sometimes it stumbles for a couple seconds, but then starts. If it stalls, it always starts on the second attempt. Now, when I notice the rough start, I'll hit the gas which usually gets it going. Maybe a few seconds of rough idle and then all is good. No noticeable performance losses. There seems to be no trend related to cold starts or hot/cold weather. It seems more common after the engine has been warmed up and is then parked for an hour or so, but that's not 100% either.

4 months ago I did:
Oil/Filter Change
Intake filter changed
Replace valve cover gaskets
Replace all 6 spark plugs and coil packs

2 months ago I got a CEL for random cylinder misfires and cyl. 1,3,6 and took it to the mechanic:
Fuel trim was -13.4%
Replace all 6 fuel injectors and orings
Intake carbon cleaning (walnut blast)
PCV valve replaced
Smoke test intake - no leaks
Clear codes

Today the check engine light came on again. Scanned and got multiple/random cylinder misfires and cyl. 2,3,5,6 misfire. Could this be a fuel filter, fuel pump, or fuel pump control module? Does anyone have other ideas or simple ways test before part swapping? Maybe crank or cam position sensor?
 

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Sounds like a cold start procedure fault to me. There should be a sensor somewhere that tells the ecu to richen the mixture. Which appears not to be triggering on the semi cold start. Hence the correct start with a bit of gas.
Do you use the car on short journeys from cold?
 
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