My 1.8 has been doing something for a while, just wondering if anyone else's does it or if there's any advice?

 

When I'm just cruising, with my foot only just on the throttle to keep it along at a steady pace, it feels ever so slightly like it's juddering or shuddering a bit, a little like it's either starved of fuel or something's not running quite right. Any other time, when you give it a little more to make progress in traffic or at idle, it's running perfectly smooth, no lumpy idle, nothing.

 

Any ideas?

Anyone?? :(

How many miles has the car done? Is it showing any fault lights on the dash?

It's just ticked over 70k and apart from it feeling a bit lumpy (mainly it seems for a while after it's started) it's still running as tight as it was when I bought it. Apart from the hesitation feel, it's working perfectly. Might be a stupid question, but would the sparks be a possibility? On cars I've serviced in the past, I always changed them every year, but Skoda have this odd thing about doing it when they're needed and this is a new thing to me. And oil type/quality wouldn't make a difference would it?

 

Oh, never had any warning lights at any point in it's life except when I disconnected the battery and it needed the standard 100 yard drive to clear them.

Edited 20 September, 201510 yr by blackspaven

It could be the spark plugs/coil packs, but worst case could be a build up of carbon deposits on the valves.

I had the same type of problem with my previous car, a Mazda 2.0 petrol sport. Around 2k revs it was doing what yours is doing. It also had a slightly uneven tickover. Turned out it was the egr valve sticking with carbon build up. New one fitted, problem solved. Did not get any codes come up either, just a good mechanic made an educated guess.

Idle is as smooth as silk, just a little lumpy when I'm just tickling the accelerator to maintain a constant speed like 30mph or summat. Pickup when accelerating is fine. It's one of those ones where only I or another loving owner would probably notice if it wasn't pointed out.

 

You say carbon deposit is worst case scenario, why's that and is there nothing you can do if it is that?

Have a read of this thread: http://www.briskoda.net/forums/topic/273037-vrs-20t-fsi-stuttering-at-idle-and-on-acceleration-up-to-2000-rpm/

 

It also suggest other things that could cause the hesitation.

Look at spark plugs first - down here the book says 90k km (60k miles) changes for the 1.8tsi but I know the dealers do them at 60k km (40k miles).  But being AU that might just be another money spinner for the dealerships.  Make sure you check the gap - off the top of my head it's 0.7mm.

 

Coils - maybe.  If you can pick a set up for a reasonable price I'd change them.  I paid AUD140 (GBP70) for a set of the red tops a while back.  Cheap insurance.

 

Unfortunately, it does sound a bit like carbon build up in the inlet - your at about the right mileage.  You can check with a cheap endoscope through the inlet temp sensor hole.  Maybe try some foaming inlet cleaner to shift some of it or do a high volume chemical clean - both have varying levels of success.

 

Prevention is by way of a catch can in the PCV system.  Supposedly 504.00 oil reduces the risk as well but I'm on 504.00 and I empty 500ml out of my catch can every 2000km.  Horrid stuff.

 

You might also try an Italian Tune-Up  - it won't clean out any gunk but the valves will move a fraction more and shift the gunk down the valve stem a few thou so that the valves are seating properly again.

If it is carbon build up is it usually a head off job? :(

 

Don't suppose the 1.8 has that indirect injection like the R32's and other Vw's as they're supposed to clear carbon build up whilst driving?Ju

 

Just read quite a few posts on carbon build up on here and they all seem to have erratic idles whereas mine is solid as a rock at about 850 so hopefully it's not that.

Edited 22 September, 201510 yr by blackspaven

head stays on, inlet manifold off.

 

look at the easy  / cheap stuff first

If it is carbon build up is it usually a head off job? :(

 

Don't suppose the 1.8 has that indirect injection like the R32's and other Vw's as they're supposed to clear carbon build up whilst driving?Ju

 

Just read quite a few posts on carbon build up on here and they all seem to have erratic idles whereas mine is solid as a rock at about 850 so hopefully it's not that.

Can you feel a twitching on warm idle? Like something is kicking the seat every second or so?

I'll check next time but I'm 99% sure there's nothing like that going on. It's literally only when you're maintaining a certain speed with your foot tickling the pedal to stop the car naturally slowing down.

 

I'd also add here that I'm guessing it's still the case as it was back when that short journeys are a killer as they create more sludge cos the engine doesn't warm properly, but I'd say that at least 70% of my journeys have been a minimum of 20+ miles, if that's likely to make any difference.

 

Anyone think it's worth sticking a few tanks of Vpower or the like through the old girl? And what about fuel additives, any good and if so any recommendations? Please don't anyone say Terraclean, it sounds horrendous!! :S

Edited 23 September, 201510 yr by blackspaven

90% of my journeys are 45km - I still had carbon excessive carbon on the inlets at 90,000km.

 

I use 98ron all the time.  It has no effect on cleaning the inlet valves as the fuel is direct injected into the cylinder.

 

I do this:

https://youtu.be/hHF-Jdw0eto using a mixture of degreaser, mineral turps, methylated spirits & water.

 

Finishes up like this

Cyl 2 before & after

Cyl 3 before & after

Edited 24 September, 201510 yr by brad1.8T

Can you feel a twitching on warm idle? Like something is kicking the seat every second or so?

 

Checked yesterday, when at a standstill, apart from when I start it up and it's running at about 1200rpm where it's a little juddery, after a minute or so and it settles down to it's normal 800-850 rpm it's smooth as silk. If you were test driving it, the idle would be perfectly acceptable.

 

So the sparks were changing about 18 months ago, gonna try a few tanks of v-power but does anyone have any additives they'd recommend? Thanks Brad, but just don't trust myself with making my own without ballsing up the engine!!

I've recently been wondering if I have a very faint hesitation under light load too, but it might just be in my head! Suspect it is probably coking if anything, but I intend to pull out the turbo diverter valve soon just to check there are no tears in the diaphragm.

 

I've also just changed the fuel filter this morning and that is a nice easy 30 minute job. I'd recommend anyone with a TSI Octavia serviced by Skoda do the same now; they didn't see fit to put an interval on the petrols so you are probably still using the original filter!

 

 

The official VAG part is 1K0201051K. I'm not sure what the dealers charge but it is available on ebay for £19;

 

http://www.ebay.co.uk/itm/321192083475?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

 

 

Here's the gunk left on some filter paper after I drained my old fuel filter into the lawnmower. Can't waste good V-power!

 

It seems there are a lot of similar issues and symptoms all caused by a range of parts.  Pinning them down is a nightmare!