Odd idle speed when cruising in Auto Tig

**smipx013** · 04-01-2010, 09:25 AM

Hi,

I have a 2009 Tiguan Auto Diesel and have noticed recently that, when cruising along, if I take my foot off the gas pedal the revs drop to idle.

The revs only pick up again if I touch the accelerator. Im sure it did not used to do this. If you feather the gas pedal to maintain a set speed (say 50mph) then this can have the effect of the rev counter dropping to idle and going up again to, say 2500 rpm all the time.

Any idea what the problem could be? ps. the Tigual Auto box is not DSG it is regular Auto and it is also 4motion.

I have noticed the haldex doing its thing in D2 when pulling off, you know that wierd bit where the revs drop a bit even though the geear is not changing. This is a little similar to that but not the same....

Cheers,
Paul

**NZTiguan** · 04-01-2010, 11:30 AM

So while you're traveling at a constant speed the revs are going from idle (800±) to 2500 and back up and down ???? sorry but I don't see that this is even "possible" as at a constant speed the torque converter is locked up so the revs / speed is constant ?? Then you're saying it slows down when you take your foot off the gas ?? well I hope so, cos that's what it should do ?? Sorry but I just don't understand exactly what you're saying.

As far as the "shift" at just below 20kph in 2nd goes: This is the Haldex system going from 50/50 (which it engages for "take-off") to 90/10 cruising. It "feels" like a gear change and many people who don't have the MFD showing the gear they're in are "convinced" it IS a gear change but it isn't. Perfectly normal and all of them do it.

Cheers

**smipx013** · 04-01-2010, 06:17 PM

Hi,

What I'm saying is that if I am going along in D6 at 110kph and take my foot off the throttle the revs drop to 900rpm immediately. It is still in D6 not Neutral. It was not doing it before - before the revs would drop slowly as the car slowed. As soon as I touch the accelerator again the revs jump up to the revs where they should be at the speed I am going (e.g. 2500 revs). Its like the box is kicking into neutral every time I lift.

Paul