Little gap in enginen running

[robotsyte]

Hi everyone!

I have a problem with my Seat Ibiza 2002 1.4 16v (BBY). Sometimes when it is running, a small gap is comming, in the engine run and than tha engine run again without any trouble code. When you drive, you just feel, like you push the brake softly for a sort time and than got again. I have this problem since 6-7 years, so I have some experince, but unfortunatally, I cannot find the reasones. It can happans during the summer and winter too. With high rpm and with low rpm. Sometimes 3-4 times per day sometimes not comming for 3-4 months.
I read in another forum exactly the same problem with the same type of car, but there were some tips but no final soluiton.
Any of you have/had the same probelm, what can be the solution?

Thanks!

 

[RUM4MO]

What I had with my wife's 2002 Polo with that engine, was what felt a bit like you were lifting your foot from the throttle pedal, almost like a surge in as much as power was dropped slightly, this mainly only ever happened when running with a light engine load.
Just before this happened, I had run adaption using VCDS on the Throttle Body, after cleaning it using something like injector/carb cleaner spray, I think that this feeling disappeared with time as maybe the engine's ECU relearned some fuelling values.
Round about this time I had cleaned then replaced the MAP sensor, cleaned out the EGR gas passage below the Throttle Body, which was blocked and had started reporting EGR flow faults, due to that car using too much oil, and so suffering from pre-igniting as a result of the trimmed fuel value leading to the overall fuel octane rating being reduced as the oil was taking the place of the petrol. I eventually replaced the oil separator and that reduced the oil usage and the pre-igniting, but before that I had started using only 97/98 octane petrol to stop the pre-igniting, and that engine ran far better, especially at low revs, so it had become more drivable - and my wife liked that, so she would not allow me to change back to 95 octane petrol after replacing the oil separator!

So, is your car's engine using/burning its engine oil, if so try to fix that, typically these engines do not suffer from bore wear so if it is using/burning oil, then something is wrong with either the crankcase ventilation or as in my case, the oil separator which some people think should be replaced after maybe 8 or so years.

One other thing, we had that Polo 1.4 from new until it was 13 years old an 105,000miles, and I never ever replaced the fuel filter or fuel pump, so any reduction in fuel pressure due to pump wear or filter chocking, or the injectors needing cleaned out, could all lead to a reduction in delivered fuel quantity and so lead to surging or irregular power delivery, it will be a case of doing all the cheaper "things" first.

 

[robotsyte]

What I had with my wife's 2002 Polo with that engine, ...

Sounds interesting what you wrote. For me it a bit more hard then I just release the throttle pedal. Because when I just release the pedal, the engine still get some fuel and just slowing down, but during this short power gap it is more like there is no ignition or fuel for a short time, and a hard engine brake is happening. But without trouble code, hard to say which one. So interesting for me, if some main thing is missing during the enginge is runnig why the ECU doesn't store anything. For me this mostly happens when the engine has normal engine load. few time during an overtake and few times during a waiting next to red lamp (in that time the engine stop).
I changed 5-6 years ago the fuel pump because of a hard cold start(the change solved it), and few years ago I also changed the fuel filter, but the problem still happens.
What I realized,(but maybe it just moved me to the wrong way), this engine type kills the ignition spark transformers so often. And before a transforemer will died this gap in the engine power happens more often. I would say maybe, because as I wrote some times I cannot meet with the problem for months.
Yes you are right, my car's engine also using to much oil now (0.5-1l/1000 km), but this is happening since 1 year only. and the main problem is comming from the time when I bought the car, 6-7 years ago.
You think, this high oil usage can makes this issue?

Thanks!

 

[RUM4MO]

Using oil instead of fuel, which is what it is forced to do as the controlling Lambda sensor will see too rich a mixture so shuts back the base/basic fuelling will cause lots of running issues.

One thing to forgot to mention is, have you checked all the rubber air/vac pipes, especially the brake servo pipe is well known to start to split where it gets fitted to these plastic barb connectors - and usually these splits are out of sight, ie "behind" or "below" from where you can look at, very annoying!

I'm just trying to give you as many suggestions as possible.

The COPs that engines have, ie Coil On Plugs, for a few engines of that age, suffered from probably VW Group demanding that their suppliers moved their manufacturing plants to some "less developed" areas - and that caused too many coils from proper manufacturers becoming very unreliable, these problems will now have been solved, but many people are just buying cheaper and so very unreliable coils instead of Beru or Eldor who were the original supplier of coils to VW Group. My wife's 2015 Polo has Eldor manufactured in Turkey, and I am worried!! Always replace the plugs before they start to fail as they will kill these coils if they go faulty, I would only ever fit NGK plugs to VW Group cars.

 

[robotsyte]

Using oil instead of fuel...

Yes you are right when the oil is going into the burning area this is never good, but I'm not sure but maybe the engine renewing will be more expensive than the whole car's price.
I have to thinking on it.

I check few pipes, but not all, following your ideas, I will check all, maybe I can find some damages.