Shudder and not shifting

Jeeper44

New member
Joined
Mar 27, 2011
Location
Maine
TDI
'06 Jetta
For a while now my '06 Jetta BRM has an issue when trying to accelerate with a bad shudder. If I accelerate slowly the car is fine but if I step on the throttle then it starts. When I leave work there's a hill I have to climb and if I try to speed up to fast I have a problem. If I give it a little throttle and keep the RPMs under 3k then its fine. If I were to take off from a stop and floor it, the car would shake and shudder a lot. It seems to do it more in 3rd gear than any other, but that could be a coincidence.

Lately I've noticed on one long hill I have to go up that the transmission will shift into 3rd as usual, the RPMs will climb up to about 3k and then just sit there. The car won't go any faster, pressing the throttle to the floor makes no difference and it won't upshift into 4th. As soon as I reach the top of the hill and let up on the throttle a little bit, it accelerates normally. The car isn't shuddering at this point, just won't accelerate.

I thought it was a transmission issue. I was worried about the DMF blowing up, so I've really tried to baby the car. Now I think its probably a fuel/boost issue.

The car starts great, idles fine, has no black smoke when trying to accelerate and as long as I'm not in a rush and use small throttle inputs runs great. I have a new fuel filter on order so in a couple days I will be changing that. I did the timing belt last week and the problem hasn't changed.

If its not the fuel filter, than I will look at the mass airflow sensor. Sounds like it could be a boost issue based on my reading here and other forums. I welcome anyone else's insight to where I might look. I have 119k on the engine and I have not checked for cam wear yet. I have the VCDS tool and can do diagnostics.
 

scrichy84

Veteran Member
Joined
Sep 5, 2006
Location
St. Helens, OR
TDI
2006 Jetta, Manual
Was there a soft code registered that didn't throw a check engine light? Sounds like the car throws into limp mode going up hills.
 

Jeeper44

New member
Joined
Mar 27, 2011
Location
Maine
TDI
'06 Jetta
Just an update. I did the fuel filter change yesterday. The filter was black and there was quite a bit of crud in the bottom of the housing. I cleaned it all out and filled the new filter with Liqui Moly Diesel Purge. I also did the air filter which was needed. Amazing the difference just two filters makes. The cars zooms right along now and if I floor it, it doesn't shake, rattle and shudder but kicks down into passing gear and accelerates nicely. I'm off to work today, so I'll see how it takes that steep hill. I suspect it will handle it fine.
 

aheng

Active member
Joined
May 21, 2016
Location
usa
TDI
2006 1.9 Jetta Wolfsburg Sedan
I had a fuel filter that was completely covered with thick black crud. So I cleaned the housing, replaced the fuel filter, and also did Liqui Moly Purge and Fuel Injector Cleaner. And the air filter also. And now my car zooms along great. My turbo is not getting enough kick though, so I will do more Liqui Moly on the turbo in a few weeks to see if I can loosen it up.
 

aheng

Active member
Joined
May 21, 2016
Location
usa
TDI
2006 1.9 Jetta Wolfsburg Sedan
Also I am only buying my diesel at truck stops. I guess that the local gas station doesn't turn over its diesel quickly enough to prevent the moisture and crud at the bottom of his tank from diffusing into the diesel I purchase. My local truck stop refills its diesel almost daily.
 
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