Frustrating judder on idle? Could intercooler boost pipe be the issue?

[mojo360]

Hi all. My mk2 leon Cupra has a little judder misfire on idle - no rev change or codes. It shakes the car slightly - no performance loss when driving
Its been doing it for the past 10k miles and its not really causing a problem just doing my head in

Things that haven't worked...
- All 4 fuel injectors replaced
- Carbon cleaned
- new coils and sparks
- new hpfp

- car doesnt drink oil so its a decent 2.0 tfsi compared to my old mk5

Recently it was discovered the hose conection point to the intercooler is buggerd and a temporary fix has been made to stop them from popping out. - I'm wondering if a slightly unsecure hose (despite the bodge job) would be causing this - I'm sure I've had a vacuum leak test done but maybe they didn't notice down by the intercooler??

Only other thing I could think of is some crud is in the fuel filter - but I think it was happening before it was replaced about 9 months ago.

Any ideas would be greatly apreciated!

 

[Ghostface]

I'm in the same boat as you pal, I get exactly that but I assumed it was most likely carbon or injectors as the most likely cause. What carbon clean did you have? Hopefully it was the walnut clean...
I haven't done anything to mine yet except change the fuel filter on last service which didn't do anything to help.

 

[mojo360]

I'm in the same boat as you pal, I get exactly that but I assumed it was most likely carbon or injectors as the most likely cause. What carbon clean did you have? Hopefully it was the walnut clean...
I haven't done anything to mine yet except change the fuel filter on last service which didn't do anything to help.

Yeah it was a proper full on walnut blast. Mine had developed a really bad misfire that turned out to be the injectors. They were all in pretty bad state so I had hoped that was the issue. Its much better than it was - and feels so much more responsive and powerful after the carbon clean. Still doing the little idle shudder every 10 seconds or so though. Like I said they diagnosed a loose intercooler hose that I'm wondering might be causing a small intermittent vacuum leak

 

[Ghostface]

And if like mine you press the throttle just lightly it disappears too?
I'm gonna have a look over mine when I service it soon and I'll check around the intercooler now you've mentioned yours.

 

[mojo360]

And if like mine you press the throttle just lightly it disappears too?
I'm gonna have a look over mine when I service it soon and I'll check around the intercooler now you've mentioned yours.

Yeah only seems to happen when its sitting around 750rpm idle. Sometimes it goes a few seconds without doing it then it'll shudder a little bit with a little popping noise from the exhaust then goes back to normal for a bit. Like you I thought it was maybe a slightly dodgy injector or the carbon build up. - While it feels loads more powerful, better mpg and louder exhaust note its still got the pesky shudder.

Is yours remapped? Mines stage1

Yeah they found the two pipes that go into it really loose and ready to pop out. They put some screws through it for now to hold it - no real difference after they did that so I wonder if its seal is rubbish. Yeah let me know if you have the same loose connectors - I need to go under the car and see for myself how loose is loose and then see if i can secure them better. I can't be dealing with a new intercooler. Literally just shelled out for all new injectors haha

 

[Ghostface]

Mines standard. Surely you'll only need new hoses and clamps, if your saying you've got performance increase better mpg and stuff I'd say your intercooler itself is fine.

 

[mojo360]

Mines standard. Surely you'll only need new hoses and clamps, if your saying you've got performance increase better mpg and stuff I'd say your intercooler itself is fine.

Yeah mine started doing the little shudder after the pcv valve went spectacularly at about 96,000 miles - before then it was smooth (or as smooth as these engines get) Had the PCV (and then the HPFP) replaced and its been there ever since.

Ah well its a bit of a nightmare though because the intercooler boost pipes on the Leon cupra (unlike the s3) has a really stupid connector that is supposed to like click into the intercooler 'hole' so to speak - the tabs inside the intercooler bit wear down and make it impossible to latch even with a new pipe (or so I've been told).

Yeah I'd be really effed off if I needed to go for a new intercooler - my cars only stage 1 and at 110,000ish miles its not really worth it at this stage for me. Only gonna keep it for another 15k or so.

 

[Crezzlin]

My 07 Cupra 2.0 tfsi does the same at idle, been like that all the time that I've had the car, 3yrs! Just replaced the coil packs and plugs and still does the same, but the new new Bosch coil packs have made the motor feel much smoother.

 

[mojo360]

My 07 Cupra 2.0 tfsi does the same at idle, been like that all the time that I've had the car, 3yrs! Just replaced the coil packs and plugs and still does the same, but the new new Bosch coil packs have made the motor feel much smoother.

It's so strange. I've seen S3 posts with the same issue. Well frustrating. It's intermittent and doesn't make any difference how the car runs. Ah well just have to live with it for now I guess

 

[batmannn]

It's so strange. I've seen S3 posts with the same issue. Well frustrating. It's intermittent and doesn't make any difference how the car runs. Ah well just have to live with it for now I guess

I've tried this and if the miles have built the idle air valve will be my next part, ,,, to reset the idle air valve....start engine with foot slightly on pedal for 5 seconds, then turn off engine take foot from pedal , count 10 seconds..restart engine., , this has worked on my seat toledo (follow off u tube) , am now pursuing vacuum leaks and replacing air inlet manifold gasket with a clean up under that too even after a cleaned egr, full service, still getting 0402 insufficient air to egr fault.....