[1.9liters]

I've had a frustrating, on-going issue that the dealer seems is unable to diagnose. I'm in Illinois.

For the past year or 2, my 2015, 535d X-drive, 59,000 miles, often has a barely noticeable to violet stumble and hesitation within the first minute or 2 of engine start. The rpm's can drop by 100-200 or it will just feel like a little hiccup.

This doesn't just happen when it's in park, it will frequently happen when I'm in drive and the engine is in 1st or second gear. There is a noticeable hesitation in power delivery when it happens.

The issue seems to be more prevalent in hotter weather but I can't say for sure.

Things I've done to try and fix. :

--Taken it to the dealer 3 times. "we can't find anything"
--I've tried switching fuel stations for a couple of fillups, issue remains.
--carbon buildup was removed around 10,000 miles ago, issue remained.
--recall for the ECU cooler was performed,...issue remains...
--fuel additive, issue remains.

I'd appreciate any additional help I can get. Thank you.

P.

[Fknid]

Fuel filter change? This is pretty cheap and maybe something to try.

[Fknid]

Maybe glow plugs? On first start of a cold engine (not sure what outside temp is required) the glow plugs promote burning of the fuel.

[auntulna]

I would replace fuel filter too. I've done it, the main hassle is the fiber panels that must be removed to get to it. Annoying. Also verify with dealer that they checked fuel pump function.