Random rough idle/stumble

LKN

Well-known member
Joined
Aug 2, 2017
Location
Charlotte,nc
TDI
2004 Passat TDI
I have an 04 Tdi Passat.

About three weeks ago it threw a code for the coolant temp sensor, so I ordered a new one. I had to rush out of town last week, so it was replaced right before a 1,500+ mile trip. Code went away, and hasn't been back on.

The car has been randomly idling rough while in park/drive. It almost goes back to normal if you toss it into neutral. It just started doing this, but it won't always do it. Runs completely fine, when driving around though. No smoke. Also I haven't noticed the tach move at all, so it might just be a bad vibration? It's also been harder to start

It's had quality VW 501.01 oil changes it's whole life. I didn't have enough Pentosin to do an oil change before I left, so picked up Mobil 1 turbo diesel truck stuff. Highly doubt that caused any issues.. The cam was replaced with a Colt billet cam 15k miles ago.

Any ideas? It's not tossing any codes either.

The car has 331k miles, and I want to see this thing keep going the distance.
 
Last edited:

LKN

Well-known member
Joined
Aug 2, 2017
Location
Charlotte,nc
TDI
2004 Passat TDI
Looks like the tensioner slapping around here and there.

Another common alternator pulley it looks like!
 
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