This morning when I started my Octavia (1.8 20vT vRS) it seemed a little 'lumpy' I let it idle for a few moments, as I always do on a morning. I turned the AC on and the engine stuttered, I thought it was going to stall. When I drove away the power was very jerky and again I thought it was going to stall. After a couple of minutes it was fine and back to it's normal self. The same thing happened when I ran the car from cold this evening :thumbdwn:

The Maf was changed around 5 months ago, as was the temperature sensor. Plugs were done around 10k miles ago, oil and filters were changed last month.

I have recently changed the Recirculation valve - could this be related?

I don't have vag com.

Thanks

Hi Phil,

Could you have disturbed anything when changing the exhaust. Not sure if these cars have a sensor kicking around in there??

Cheers

Hmm that's quite possible.... Thanks, it's a good thought. I did notice a sensor in the front pipe....could this be causing problems?

Hmm that's quite possible.... Thanks, it's a good thought. I did notice a sensor in the front pipe....could this be causing problems?

Isn't that the lambda sensor? Might be worth checking it.

I'm guessing it's the lambda sensor, yeah. I'll check it visually in the morning. Thanks guys.

This sounds exactly like the problem I have.

This sounds exactly like the problem I have.

Well that rukes out the cr@p English weather then!

if its like my mates tt there is 2 lamba sensors on it one before the cat and one after the cat

if its like my mates tt there is 2 lamba sensors on it one before the cat and one after the cat

Thats correct there are 2 lambda's on that car the 1 at the front is what adjust's the mixture the 2nd one checks cat effiency but will effect performance if its knackered there isnt as such an easy way to tell (vag-com dosent check it) u can log the lamda's to see what the mixture's doing however.

Lumpy idle is normally down to throttle body needing realigning and cleaning or temp sensor or if the cars doing really good fuel wise then it could be a split breather pipe,i have had to do all 3 things on my car recently.

Exactly the same problem with my 1.8T 4x4 Octy, been happening for the last 6 months. Dealer couldn't pick up the fault as they never started it cold but they'll hopefully have a look now it's in for a while for something (possibly) rather more serious. Nothing showed on the VAG-com, though.

Well it's logged "17536 - Fuel Trim: Bank 1 (Mult): System too Lean" fault three more times now, always when I've been driving along at about 50kph in 3rd or 4th gear.

I had a thought - my Air-fuel gauge is connected into the output from the lambda sensor - maybe that's broken it?

When driving at constant throttle between about 2000 and 3000 RPM the car surges, then the revs drop, then it pick up, then the revs drop and so on. While this is happeninig the Air-fuel ratio gauge is diving from rich to lean to rich to lean.

I've reset the throttle body using VAG-COM but I haven't cleaned it yet.

I have also had a similar problem for months now. It always happens when the car is cold and splutters along for about 1 minute to the point that you feel its just gonna break down. I took it to the dealer who changed the temp sensor but that hasnt made any difference. I thought it might be the coils but they did a diagnostic check and said they were fine. I have noticed that quite a few are starting to have this same problem but no-one seems to know the cure. I have to say that when the car is warm it is fine. I wonder do you do a lot of short journeys?

I have also had a similar problem for months now. It always happens when the car is cold and splutters along for about 1 minute to the point that you feel its just gonna break down. I took it to the dealer who changed the temp sensor but that hasnt made any difference. I thought it might be the coils but they did a diagnostic check and said they were fine. I have noticed that quite a few are starting to have this same problem but no-one seems to know the cure. I have to say that when the car is warm it is fine. I wonder do you do a lot of short journeys?

I don't know whether this will help but i never attempt to drive until the secondry air pump stops spinning when the car is cold usually takes about 1 minute i my experiance it drives like crap whilst the pump is working you may find this is your problem if it is it is entirly normal afaik

Mine drives fine after the 1 minute wait

Try waiting 1 minute you never know

HTH

Well it's logged "17536 - Fuel Trim: Bank 1 (Mult): System too Lean" fault three more times now, always when I've been driving along at about 50kph in 3rd or 4th gear.

I had a thought - my Air-fuel gauge is connected into the output from the lambda sensor - maybe that's broken it?

When driving at constant throttle between about 2000 and 3000 RPM the car surges, then the revs drop, then it pick up, then the revs drop and so on. While this is happeninig the Air-fuel ratio gauge is diving from rich to lean to rich to lean.

I've reset the throttle body using VAG-COM but I haven't cleaned it yet.

Sounds like an air leak to me, check all the hoses etc..

Exactly the same problem with my 1.8T 4x4 Octy, been happening for the last 6 months. Dealer couldn't pick up the fault as they never started it cold but they'll hopefully have a look now it's in for a while for something (possibly) rather more serious. Nothing showed on the VAG-com, though.

In order to comply with emissions the 1.8T has a warm up cycle to get the cat up to temp as quickly as possible, it involves extra fuel & you can hear an extra air pump running so Im guessing the cold start problem is something to do with this, I had similar problems when the bigger Turbo & jets were fitted. Interestingly its been virtually cured by fitting a different injector which has a similar spray pattern to the stock ones. The diagnosis was that the original bigger injectors were spraying the fuel in & washing away the spark. It had originally been reduced slightly by fitting new plugs.

Try starting the car, run for about 30 seconds, turn it off, wait about 30 secs & restart, this sometimes tricks the starting cycle, if this makes a difference then Im guessing this is where the problem lies