2001 Passat idle studder??

[MachineMan]

Our 2001 Passat wagon 4cyl turbo automatic has a random idle studder. When sitting at a stop light the RPM's quickly drop and then regain idle. It happens at random times and only when idling. It doesn't seem to matter if its in drive or park. Any idea on what sensor could be failing or a possible cause? Over the past year the problem has increased from almost never to a few times at every stop light. My OBDII reader shows no codes. Car has 101K miles.

Thanks..

[wakebdr]

This is in reply to your posting in my thread.

I cleaned the throttle body in our passat and that seemed to take care of the issue. It's a relatively easy thing to do.

http://www.taligentx.com/passat/main.../throttlebody/

[twenty4valve]

Originally Posted by wakebdr

This is in reply to your posting in my thread.

I cleaned the throttle body in our passat and that seemed to take care of the issue. It's a relatively easy thing to do.

http://www.taligentx.com/passat/main.../throttlebody/

Very much be the cause.

[MachineMan]

I will check it out and post back. The TB has never been cleaned.

Thanks.

[MachineMan]

Cleaning the throttle body did not help. It was actually fairly clean to begin with.

More details: The idle probem does not show up until after the car has warmed up. This should be a clue that it only happens after the computer swithces to sensory control once out of closed loop. Also the problem is not constant, it will be fine and then every 5 to 10seconds or so it happens.

[Kaos]

you may have a vac leak. check all conections . if you have a boost gauge with the vac an boost like the VDO one you should see it dropping vac presure.if all lines an conections are good you may also be looking at a intake gasket leak. but the vac testing will help.