I'm having a nightmare with my vRS, it is really struggling to idle and will barely tick over, it keeps missing and popping on idle and when the revs drop down it is hunting quite badly, it is really doing my head in, I've just changed the air flow sensor and it worked fine for about 20 miles then its started doing it again and the engine light has come on, its a right pig to drive at the mo, I'm running a K&N cone filter and a standard recirc valve.

Anyone have any ideas?

Any help greatly appreciated as I need the car for work!!!!!!!!!! Cheers!

A VAG-COM scan would be a good start.

There are often issues with slightly split pipes that crop up during the colder times.

it might be a duff coil pack or even something like a lamba sensor.

Like stu said a vag com scan will tell

I've just had a look this morning and I've found a split pipe but its on the top of the rocker cover, not quite sure what its for?

Also I havent got VAG-COM, can you download it?

You can download a trial version but you' still need an interface.

Try the members register in the VAG-COM section for somone near you.

Where are you?

Does it lead to the dumpvalve?

is it the Y shaped pipe?

Failing to idle is a classic sign of faulty water temp sensor in any modern car. You should consider this as a possible problem too.

I do know that the temp sensor is fudged and have a replacement ready to go in this weekend.

I went for a drive into the Derby dales yesterday and it was hesitating at low revs e.g below 2000rpm, once I got back and left the car to cool down it hasn't played up since, but the EM light is still on.

As for the split pipe I'm not sure where it goes, I'll have a look now and post up when I've found out. Cheers

Right, I have now changed the fuel (both ****e and V-power) no difference, air mass sensor - no difference, coolant temp sensor - no difference (also the temp gauge still drops off 90 deg).

The split pipe is the y shaped pipe which leads to the main turbo inlet via a big valve thing! Ordered a new one will arrive tomorrow.

And its still playing up!!!!!!!!!!

Where abouts are you?

I'm in Nottingham mate, now have the Y pipe so thats going on tomorrow, can't see how it will get rid of the engine light, got a feeling thats something else, be glad when its sorted should run for a while after this!!!!!!!!!!!

Now I can't understand why the temperature gauge is still floating even tho I've changed the coolant temp sensor, unless theres a seperate sensor for the gauge?

now have the Y pipe so thats going on tomorrow, can't see how it will get rid of the engine light, got a feeling thats something else, be glad when its sorted should run for a while after this!!!!!!!!!!!

I ordered the Y pipe but it was the wrong part in the bag

I got the temp sender to go in also but I don't have anywhere near as bad a problem as you do :eek:

I hope it gets sorted soon!

Bugger,

If you'd of been nearer to Hull I'd of plugged my Vag Com in for you to find out what your error code is.

I'm in Nottingham mate, now have the Y pipe so thats going on tomorrow, can't see how it will get rid of the engine light, got a feeling thats something else, be glad when its sorted should run for a while after this!!!!!!!!!!!

Now I can't understand why the temperature gauge is still floating even tho I've changed the coolant temp sensor, unless theres a seperate sensor for the gauge?

I'm in Nottingham mate, now have the Y pipe so thats going on tomorrow, can't see how it will get rid of the engine light, got a feeling thats something else, be glad when its sorted should run for a while after this!!!!!!!!!!!

Now I can't understand why the temperature gauge is still floating even tho I've changed the coolant temp sensor, unless theres a seperate sensor for the gauge?

Do you oil the k and n filter? if so it seems strange that the new maf worked for a short period. Could you have over oiled the air filter which could have coated the maf?

Otherwise all i can suggest is a knackered thermostat.

I did re oil the filter as I did a major service about 3k ago, maybe thats a possible cause, hope its not the thermostat been told its a cow to change.

New pipe is going on today so will post the outcome, hopefully it might be useful if anyone else has the same problem in the future.

Imo it is really valuble to post all cures to any problems.This way future searches can find the fixes without going through the post sytem and having to wait days/weeks to find an answer.

New pipe is going on today so will post the outcome, hopefully it might be useful if anyone else has the same problem in the future.

Let us know how you get on

Right Y pipe is fitted, also the standard airbox and clean brand new OEM air filter is fitted, and its still sputtering.

So that only leaves the lambda sensor and the coil pack and possibly N75 valve.

Think I desperately need a vag com scan now!!!!

Could be the throttle body needs cleaning, have anyone suggested this already to you

Right Y pipe is fitted, also the standard airbox and clean brand new OEM air filter is fitted, and its still sputtering.

So that only leaves the lambda sensor and the coil pack and possibly N75 valve.

Think I desperately need a vag com scan now!!!!

That would still not address the matter of the coated maf.You could try cleaning the maf as the new maf seemed to cure the problem for a while in the first place.

Either that or unplug it and see if it runs any better.This would make the ecu guess what air is going into the engine.I have done it before and it usually runs pretty well when disconnected even on a power run. This at least would rule the maf out.

Dunno whether i forgot to mention I put a new MAF sensor on about 10 days ago, when I took the filter off today it wasn't wet with filter oil, so I would guess this shouldn't have affected the new MAF. Could be wrong tho. Ta

Right, I've managed to get a VAG-COM scan, and I've found the following

17705 - Pressure drop between turbo and throttle valve (check D.V.!)

17704 - Error in mapped cooling system

16514 - Oxygen (Lambda) sensor B1 S1: Malfunction in circuit.

I've traced the lambda fault to the pre cat lambda sensor via the outputs on VAGCOM and it is outputting a voltage 1.5 times the maximum it should do, and also a few other readings point to this being defective.

Have ordered a new one at £129 (ouch) so will post the outcome once fitted on wednesday.

Also gonna clean the throttle body and see how much difference that makes.

17704 could well be the temp sensor.This and the oxygen sensor would explain rough running.

hello : have you had a look at your spark plug and leads ? check them when its dark for arking to earth. and second your speed sensor ? it might not be working propery and on its last legs . hope this helpful