I disconnected the battery for a few moments the other day to reset the remote locking. Since then the car occasionally (mainly on a colder engine) likes to either idle at about 15k or rev up and down between 15k and 20k. After the engine's warmed up it's absolutely fine.

I'm going to reset the ECU with this battery trick tonight once I get home to see if that works.

Thank you to the contributors of this thread!

Thought i would report back. The above worked a treat, however i found my Valver's revs falling at a junction the other day, just before it was about to cut out i rev'd her and had to keep reving her to prevent a stall. It's not happened since but it did worry me slightly.

If i clean the throttle body, do i need to reset the ECU or something? Is it a simple case of poping the throttle body out, cleaning and then popping it back in again as there are mixed posts through this thread!

Thanks in advance.

i've got a 6n2 1.4 8v - idle was all over the shop, and it was often sitting around 400rpm which meant the car would like to stall (and with a car with a silent exhaust, you try and drive off from the lights and the car doesnt move) idiot haha

anyway whipped off the engine cover, (2 10mm bolts), gave the TB a good clean with carb cleaner and a toothbrush, and replaced a couple of kinked hoses and its been sweet as a nut ever since, straight away first turn of the key.

no resetting off the TB, or disconnecting battery.

it may not solve all issues, but its a good place to start!

Got a few hours of my bank holiday weekend sorted then!

There is some complete bollocks in this thread;

1) Take off TB, clean it to fuck.

2) Clean inlet manifold where you can reach.

3) GET AN OIL CATCH Can, will stop it sludging up again.

4) Clean your PCV Valve.

5) REALIGN TB with VagCom basic settings UNPLUGGING THE BATTERY DOES NOT WORK

I also think some 16v suffer air leaks from manifold seals as it is made from 3 parts, causing air leaks. I have just rebuilt head cleaned throttle body and resealed the gaskets on inlet manifold and the poor idle has gone from our afh.

Prob sound a bit stupid ere but I dont really do much car maintenance, can anyone tell me where the the temp sender is on my 97 1.4 16v? I have had the throttle body out and cleaned it and seems to work ok for a few hundred miles or so then get the same problem with it threatening to stall. Gonna change the temp sender but just wanna make sure i'm looking in the right place first. Just started a new job and need it to be reliable, any help would be much appreciated.

Hello I'm new here and I have got a 1.4 16v 6n1. I have got the same problem too, I work in a garage so I know a few things to check. But I have found loads of info on the net.

So I thought I could make up a guide so you can work your way through to help solve this problem.

* Clean out throttle body and reset the settings

*Check all vaccum hoses

*Check any air leaks from all 3 gaskets on the inlet manifold

*Check cambelt timing

*Check spark plugs, HT leads and coil

*Check the compression of the engine it should be around 150-200 psi

*Blank off the EGR valve

*Check wiring to all sensors and things

*Fit new coolant temp. sensor, BUT ONLY FIT GENUINE VW PART

*Fit new oxyegn/ Lambda sensor

*Fit new throttle body

*Last resort is to fit a new ECU

Well if you have gone through that checklist have not found anything wrong well don't know what else to suggest lol, But I would be surprized if you did not find anything wrong

I hope this helps for everyone

Sorry there are a few more things

Check fuel pressure

Check fuel injectors (rig up four jam jars and check equal fuel delivery on all four injectors)

Edited 20 October, 201114 yr by lenny125

Hi i have a 16v afh engine. the problem it it idles 1500-2000. the weird thing is if i disconnect the battery and reconnect it the car runs perfectly. after around 150miles the irractic idle slowly comes back and gets worse over time. to start off with the revs will bounce around 1500-2000 a bit then drop down to 1000 and stay there. overtime it will get worse and eventually it wont go back to normal idle. i have cleaned the throttle body had a service and cam belt done. i have replaced vaccum hoses. same thing happens runs perfectly when it gets around 150miles the irractic idle comes slowly back and gets worse. so at the moment when it gets really bad and wont go back to normal idle i just disconnect the battery and reconnect it. same thing keeps happening.

I maybe wrong thats why i am asking, if it was a sensor, air leak or ignition fault then after reconnecting the battery the irractic idle should come back straight away?

is there anyone that can help?

thank you

Edited 28 December, 201114 yr by aziz360

Thanks for this thread!

Got an AFH, bought it for scrap money three months ago. It didn't idle from cold, smoked on start up, then sometimes would randomly cut out for a second or two while driving.....like someone was playing with an on/off switch for fun.

Then it needed an MOT just before Christmas....total fail on emissions...MOT man said it probably needed a new cat...have you seen how much they cost?

So...checked this thread, cleaned the Throttle Body and inlet manifold as far as I could reach, as recomended in the first post, disconnected the battery for a few hours and while I was waiting I cleaned the battery earth points (and the wiring earth point) behind N/S headlamp and on the engine block.

Result! Instant cure...total transformation...drove the long way back to the MOT place to get everything good and warm and easily passed emissions test.

OK, I might have been lucky and it might not work for everyone, but it's a straightforward cleaning job and costs no more than a can of carb cleaner and a bit of time. Give it a try.

I cleaned my throttle body while still attached to engine. That worked fine for me. My problem was I kept getting gunk (mayo) coming through the breather hose! This just caused the problem to return over and over! As a temp fix I put a breather filter on the hose and blocked off the coneter to the air box. Only problem with that is smoke would rise from under bonnet!! Ended up getting the oil separator and hose replaced (which thyrned out to be completely F#!@%D) Now the cars running a lot smoother & more efficient.

I've got this problem with my 1999 6n1 1.0 aer

It was idling really low and cleaned the throttle then when I put it back and started the car back up the it was idling around 2000 so I went and got the throttle body realigned and it made no difference what so ever so then I changed the temp senda ht leads and cap plus I changed the rotor arm and its still made no difference

Any got any insight as what else it could be I've read so many threads and so many people have solved the problem by doing these things but not me hahaha

Any help would be much appreciated