135i shuddering on acceleration

[friedymeister]

I was wondering if anyone has encountered this problem or quirk.

My 2011 135i convertible, 6MT, unmodified with 31k miles, has a weird shudder during flat out acceleration on the highway. I noticed that when I go flat out or accelerate hard in 5th or 6th gear, at around 3k RPM it feels as if the rear wheel slips or there is a complete power cut out for a second. There are no warning lights, the RPMs don't fluctuate (I haven't noticed any changes), and I know the rear wheels aren't slipping, but I feel the sensation of a brief disconnect from the rear end.

I've read people commenting on similar problems, but none seem to be this one. I haven't noticed this in first or second gear, I've only seen it in 5th or 6th.

Does anyone have any idea?

[Skotcoop]

Does the sensation continue at higher RPM?

[Edrift]

Do you know what a misfire sounds/feels like?

Sounds like that... Though I'd expect a code thrown

[friedymeister]

The shuddering only occurs for a second or less and goes doesn’t return during the acceleration. I don’t know what a misfire is like, but there are no codes and no lights and it doesn’t occur in lower gears.

[sliebhard]

Originally Posted by friedymeister

The shuddering only occurs for a second or less and goes doesn’t return during the acceleration. I don’t know what a misfire is like, but there are no codes and no lights and it doesn’t occur in lower gears.

Possibly your HPFP.

Any cold start issues or limp mode?

[friedymeister]

I've had long cranks since the car was two years old. The dealership replaced the starter without improvement, generally only happening during cold starts. If the HPFP were causing this, wouldn't it happen in any gear?

[dtla1]

Originally Posted by friedymeister

I've had long cranks since the car was two years old. The dealership replaced the starter without improvement, generally only happening during cold starts. If the HPFP were causing this, wouldn't it happen in any gear?

Usually more common under high load situations, low rpm in higher gear. That was the hints with mine going out. Eventually it would go into limp after trying to accelerate.