Lumpy Idle- 2005 mk5 gti k03 axx

[Craig Stanley]

Hi. Can anyone shed some light on why my car idles fine until the temp gets upto 90° and the fans cut in and then runs with a slight jerk roughly every 3 secs. I have done the cam follower, new pcv, dv and air filter. The spark plugs were replaced by the previous owner about 2 years ago but have only covered about 8000miles. Should I replace them and change my coil packs?? Would this maybe help?? Or is this just the characteristics of the engine.Advice would be much appreciated. Thanks

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[stuart-88]

The jerking could possibly be your inlet valves clogged up with carbon. Get it plugged in to check for fault codes, if it doesn't show up with anything obvious then I'd definitely look at getting them cleaned.

[Kieran1990gti]

I found a remap cured my lumpy Idle always flagged up with a timing error or something after remap it's never come back and car runs loads smoother, cheaper option that getting inlet and valves cleaned

[Craig Stanley]

Thanks for the replies. Got it booked in for a remap at rtech on 30th July so fingers crossed might sort it.

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[stuart-88]

The jerking could possibly be your inlet valves clogged up with carbon. Get it plugged in to check for fault codes, if it doesn't show up with anything obvious then I'd definitely look at getting them cleaned.

@stuart-88 Stuart, have you experienced this in the past? After a spiritied drive, my axx seems to "surge". Its hard to describe it but it isnt a consistent continuous hum like it should be (minus the noisey injectors obviously). Im wondering if it could be inlet valves clogged up - it is on 110K.

Sorry to hijack, althought it sounds like our problems might be related

I had a lumpy idle from when I first got my Golf. Replaced various problem parts but it wasn't until I cleaned the inlets that it finally cleared. I've done mine at 60k miles and a friends on 80k and both were in a bad state. My friends was bad enough for his to cut out on cold starts. Obviously I can't say for sure if that's your issues but I wouldn't rule it out.

If you're competent at doing it yourself, it costs about £60 in parts and an afternoon 

Good luck at R-Tech Craig, I'm booked in for Friday 

[Craig Stanley]

It doesn't do it at all on cold starts or any other time, in fact it runs and purrs like a kitten with no chain noise or tapping, until it hits 90° and the fans cut in and then it just has a slight jolt on tick over. It has done 77000m and I will get the inlet cleaned its just I want to spend my money on more fun mods for the car. Cheers:)

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[Craig Stanley]

Hope Friday goes well. Post your results when you get them. Interested:)

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[Dan_FR]

A remap will not fix a physical issue with the car, such as clogged inlet, sensors etc.

If the car is not healthy Niki will turn it away so it's in your best interests to get it healthy before mapping. Get it on VCDS, find someone local if need be, and get an understanding on whether the car is running well or not. It could be a simple plug/coil or it could be something that is a potential engine killer, especially once tuned, such as a weak injector

[Craig Stanley]

Had it scanned and has no faults, missfires etc.

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[Craig Stanley]

Also as mentioned above all common problems with these engines has been done. Been into 2 seperate vw specialists in the last 2 months for all the work. As I said it runs fine and then runs a bit lumpy once fans are working. I know inlets will be coked up but was just thinking maybe new coils or plugs. Thought it might be a weak spark once the fans are on. Thanks

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[stuart-88]

Mine is r-tech stage one and still has the funny idle, especially once its been for a spirited drive.

@stuart-88 I think i'll look into cleaning the inlet. What is the £60 for? Are there any specialist tools - I think I've read about an injector removing tool? Would you say the work is difficult, or just time consuming? Any particularly tricky bits to watch out for?

The injector seals are £40, you have to buy the full set but only need the little blue seals that sit on top of the injector. You don't need to remove the injectors unless you want to replace all the seals. Some would say even replacing the top ones isn't necessary but I'd recommend it. You'll also need the inlet manifold gasket. The rest is just consumables. We used carbon off oven cleaner to to get melt the carbon off. It's quite fiddly and time consuming, second time round was much easier. There is a good guide which helps made by APR on the runner flap delete, but it's mainly a guide on removing the inlet. No specialist tools required unless like I say you do want to remove the injectors to replace all the seals.

[Pesky jones]

So do the injectors come out with the manifold? Ive heard some "stick" in? The APR guide is no longer available unfortunately. I've found a few other guides however. Il dedicate two days to it and I should get it done ok.

[stuart-88]

No injectors should stay in the head. This is a pretty handy guide if you need it http://www.seatcupra.net/forums/showthread.php?t=385217

[Dan_FR]

Had it scanned and has no faults, missfires etc.

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A fault code scan can be done by any £10 code reader. I mean look at live data - you cannot rely on fault codes to determine if a car is healthy or not. Have either of these specialists been tasked with fault finding for that particular issue? If not, then they won't have looked in to it any further than a basic fault code scan, which is often useless unless there is a major fault

@Peskyjones One APR guide sir: https://www.goapr.com/support/install/Accessories/2.0T_FSI_RFD/fsi_runner_flap_delete.pdf

Injectors should stay in if you fully unclip/undo everything before removing the rail/inlet. If they do come out then you'll need to replace the Teflon seals. It's worth having the kit as there's no telling whether the injectors will stay put. Some come out easy, others are stuck solid and you'll need a proper tool to remove them without damage

[Craig Stanley]

Just booked it in to have it scanned and looked at. Thanks for the advice. Hopefully they can sort it.

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