2012 Passat TDI Stumbles

Hello All,

So I have had my TDI for little over a year now and this issue has been getting worse and worse. On cold starts (as in sits over night) when i start the car and drive, if i dont let it warm up it studders and stumbles. This appears to be engine related as I have done the manual mode with the trans and it happens while accelerating not shifting gears.

Also I do press on the gas pedal a little more and it kinda clears up as if it is fuel starved. As it gets colder it gets worse. Any thoughts as to why this is happening?

If I let the car warm up for a really long time, it doesnt have the problem.

How cold is it when you have these issues? What kind of fuel are you using? What kind of oil are you using?

If anything, this seems like a cold weather issue and you should probably see a mechanic or your dealer.

it happens regardless of temp outside, it just gets worse and lasts longer when it is truly cold.

example when it was 70 degrees in the morning it still had the issue.

when it is 40 degrees in the morning it happens as well and takes longer to "clear up"

and completely a pain in the butt whenever its really cold.

Oil is the manufacture recommended.

Lots of nice info in the Passat NMS forum.

This is normal, there is an exhaust flap that is closing to force the exhaust system up to temp quicker for emissions purposes. The only "solutions" are to keep the revs up. Some have had success by letting it idle for a bit before you leave, say 30 seconds to a minute. I usually end up idling mine for a couple minutes while my sister gets in the car and settled and I usually don't have a problem unless it is freezing or below.

i can let the car warm up for 10 minutes and still notice a slight stumble. not as bad as a true cold start and go.

If that is the case, take it to your mechanic or dealer and ask them to look at the issue. You shouldn't have rough start ups with 70 degree temperatures.

My 2012 Passat 6MTSE stumbled badly when it was cold outside (below 50 degrees) during the first minute and a half of driving especially in 4th gear. This happened for almost two years! Then a few weeks ago I got the P048 error code for the exhaust flap. After VW replaced it, at their cost, the stumble mostly went away. I wish they would have found this earlier. I did make the problem known to them and they said it was normal. But it didn't do that for the first two years I had it. I am the one owner of it, and I love the Passat.

TDIFan1989 said:

If that is the case, take it to your mechanic or dealer and ask them to look at the issue. You shouldn't have rough start ups with 70 degree temperatures.

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With the emissions issue out there I dont really want to take it to a dealer and spend a ton of money chasing ghosts, or them just raking me over the coals.

Just hoping that someone else may have/had the same issue and knew a fix.