Smoke on Start Up and running poorly

[tmaclax013]

So I'll start this by saying that I don't have a B8. I wanted an avant so I bought a C6 A6 Avant but I figured the B8 community is more DIY enthusiasts than the C6 community so I figured I'd have better luck here.

Basically my car was completely fine until like Thursday morning of last week. I started it up and everything seemed fine but I noticed that when I was slowing down and the car was downshifting it would rev higher than usual and it would have this weird stutter/burble/bog engine braking to the next downshift. I also noticed once I got to work that when I put the car from Drive into Park the idle would raise to like 1400RPM.

Now I wasn't super concerned with this until I went to leave work 8 hours later and when I started the car it dumped a bunch of white smoke out the tailpipes. But it only did this for maybe 30 seconds or so and then stopped. The engine was still cold when the smoke stopped and it seemed to run okay on the drive home(still had the stuttering and bogging while downshifting). One weird thing was when I got home I put the car in park and the idle raised like I mentioned before, but when I put it back in drive to see what would happen it bogged so bad the engine stalled.

I'm still driving the car everyday to and from work(my only car rn) and besides the smoke on startup (only after the car has been sitting for a couple hours) and the strange bogging during downshifting it seems to drive fine. It also doesnt seem to be using any fluids at an alarming pace. Coolant level seems to be okay, oil is low but not excessively.

One theory I've heard is possibly a small coolant leak into the combustion chamber(maybe head gasket) that is only noticeable after longer sitting times because it accumulates of time but is not a big enough leak to notice while the car is running. Although I tend to disagree with this because I don't think it would contribute to the bogging during driving.

I'm also not 100% sure what the smoke is. It doesn't smell like oil or coolant but I'm not sure how a direct injection car would dump enough fuel to create the smoke that I'm getting.

Codes:(mostly intake related)

P0068- MAP/MAF- Throttle Position Correlation

P2004- Intake Manifold Flap; Bank 1

P2004- Intake Manifold Flap; Bank 1 (Stuck Open)

P0507- Idle Control System RPM (Higher than Expected)

P10A4- Intake Air regulating Flap (Mechanical Malfunction)

[variable]

From those codes really seems like either your intake manifold has gone bad OR the solenoid on the back of the supercharger. Check your vacuum lines on the back of the supercharger (they control the intake runner flaps). You can replace just the actuator on the manifold if that's the problem, but ultimately I don't think you're looking at a really easy solution. The reason for the stalling is essentially a stuck open flap is making your car too lean at idle. If you're a DIYer you can pull the supercharger and inspect. A hand vacuum pump will let you know if the flap is actuating or what the deal is. This is all of course assuming you haven't done any recent work. I'd start with the solenoid since it's cheap and easy to swap, make sure you buy from a reputable company because there are fakes out there that vacuum leak (speaking from experience).

[tmaclax013]

From those codes really seems like either your intake manifold has gone bad OR the solenoid on the back of the supercharger. Check your vacuum lines on the back of the supercharger (they control the intake runner flaps). You can replace just the actuator on the manifold if that's the problem, but ultimately I don't think you're looking at a really easy solution. The reason for the stalling is essentially a stuck open flap is making your car too lean at idle. If you're a DIYer you can pull the supercharger and inspect. A hand vacuum pump will let you know if the flap is actuating or what the deal is. This is all of course assuming you haven't done any recent work. I'd start with the solenoid since it's cheap and easy to swap, make sure you buy from a reputable company because there are fakes out there that vacuum leak (speaking from experience).

Thank you. I was planning on trying to address the intake codes but didnt think they could be the cause of the smoke so I wanted to prioritize that because it seems to be the biggest problem for now. Do you think any of those issues could be the cause of the smoke?

[tmaclax013]

Im starting to believe that the smoke on startup is oil. I started it today and with the angle the sun was at the smoke definitely seemed to have a blue hue to it. Plus my oil seems to be the only fluid that is being used. Not too sure what would cause the motor to burn oil that excessively on startup

[tmaclax013]

bump