Polo idle speed is near enough consistent at 1200rpm

[grazuncle2]

My Polo has, just this week, started idling at 1200 rpm. I don't mean cold.. this is at proper temp.

it has been 1000 rpm since i bought it 30 months ago but at neither the 2 services done at VW have mentioned it as needing attention.

I took the car on a motorway for half hour and kept the revs higher by staying in 4th just in case it was a regen of the particulate filter. However the car has not displayed the usual indications of a regen; hot smell or high petrol consumption.

Now for some reason it is generally stable at 1200 and on occasion 1100 rpm but not lower as in the previous 30 months I have had this car. Depressing the clutch for reverse after this long drive... sent the revs to 1400 momentarily!

Someone mentioned a vacuum pipe leak as probable cause?. I would take a look if I knew where it was. I'm loathe to take it back to VW as their service dept is rubbish, the service desk lie to you and I have no trust in them. I have a local guy who is honest as the day is long and will drop it by to him If I can't get anywhere myself.

Any other pointers please. From a few things I have researched, it seems you cannot adjust the tick over manually anyway but need VCDS. Is this right? I can't help feel though that this is not an adjustment but another issue.

I'd welcome any input.

[grazuncle2]

update with my basic Thinkcar 100 OBD reader datastream at idle.

there are no DTCs acknowledged on the scanner

Longterm fuel trim is negative I notice.. not enough knowledge to tell much on this.. anyone see anything significant

[grazuncle2]

update...

ps.. my post title is wrong .. the general idling rpm is not 1200 but 1400. misread the increments on the rev counter.

the idling is fluctuating a lot now in traffic.. after a 70mile motorway run (to clean the GPF if needed before dropping the car into VW this Friday)
the revs with foot off can now be 1200 20% of the time 1400 for 70% and occasionally 1600!

the GPF is not an issue in my mind as the stop start function operates at the drop of a hat, no hot smell and mpg average is 60.6.

I just took delivery of an OBD11 scanner... I'd like to check the soot levels but do not know where to start looking in the menus yet. I'll ask in another thread specifically as I doubt I'll get a responder for that information, in this post.

O'll report back after Friday as to what the garage finds and charges me for if not warranty.

[grazuncle2]

well today the VW garage had it in and I left it with them; they said the GPF was blocked after all and they did a forced regen..

the rpm is down to 1000 again .. I just have to take their word for it despite the lack of usual indications... they did an ECU software upgrade too.

I can't help thinking this is related as my scanner reported only 33% soot load calculated every other value was below 1%.

I don't know enough to make any statements.. i just wish I knew. However can't complain it was done under warranty

[grazuncle2]

update just to keep a record that might help others..

The software update the VW garage did has made a driving difference.. not noticed much with the fuel consumption.. it is still averaging 53mpg with local and a few trips. I the drive or power uptake is smoother.

I checked the change with my scanner and a big difference if Fuel Trim readings.. compared with those in the posts above.

Short Term FT was 1.6%
Long Term FT was -8.6%

LTFT was a bit of a worry.

since the update, with no parts like injectors replaced; they are very near perfect

Short Term FT now 0.0%
Long Term FT now 1.2%

makes you wonder what the software update did