Hi all, I'm wondering if anyone has seen this issue or could shed some light.

My 2015 Octavia VRS 2.0TDI (CUPA engine) runs fine when the engine is pretty cold or when up at normal running temperature.

For the few minutes the engine is coming up to running temperature the engine will briefly and violently lose all power, it's been getting worse and will now regularly stall when this happens. It's a nightmare as I'll inevitably be blocking a road or junction when this happens.

No faults codes.

I don't have much to go on.. AI suggested it would be the EGR valve. I went to clean the EGR but discovered it looks a nightmare to get to it on this engine. I used some Wynn's EGR cleaner but I don't think it's any better. Another suggestion from Google is the coolant temperature sensor. The temperature gauge on the dash seems to be going up normally so I'm not convinced there..

I will probably go and get the EGR cleaned. Milage is 170,000km so probably due anyway.

I have VCDS so any suggestions on stuff I can look for would be appreciated.

Thanks

A couple of things come to mind of this one:

Yes EGR and DPF issues are more common especially on higher mileage Octavia's TDI's. I suggest that if you aren't already doing it, start running your vehicle on Super Diesel for a while. You are at that mileage where injectors and heatplugs start to fail. Injector problems [where they tend to over-fuel on one cylinder) will give lumpy performance issues (and often throw no codes), heat plugs issues will cause poor starting and general roughness at cold.

I often cause controversy by recommending a fuel additive, but I only do so on that basis that it really helps the engine performance. Only use this stuff with standard diesel though: https://www.hydra-int.com/DPB000K.html - 20ml is enough for a tank of fuel and IMHO massively improves TDI performance. It is also often recommended for a fast/high RPM Italian tune-up on TDI's to keep them happy - VAG engines do not like being mollycoddled.

Thanks varaderoguy,

I'll see if I can get hold of some at that additive in Ireland. Failing that I guess there's Wynn's from Halfords.

I've also been told that mixing a litre of petrol into a full tank can help clean things up.

It had new glow plugs fairly recently as I was trying to fix a hard starting issue.