I have a 2012 Skoda Octavia VRS 2.0 TDi common rail (CEGA) engine. It’s on 139k miles, EGR and DPF in place. Full service history, oil changes every 8-10k miles, had a major service 2 months ago oil and all filters changed at a VW specialist.

A weird issue has occurred when the engine is warm. At 70mph, just over 2,000 RPM, in 6th gear light throttle maintaining speed, it feels like something is pushing the car back. At first I thought it was the wind, but it definitely isn’t. It is most common when I have to let off the accelerator and then put my foot back on, it feels like there is a restriction, it’s holding back a bit like a cough and a splutter. If I put my foot down flat it instantly clears up and the car pulls as it should. I only notice it in 6th, not 5th at 50mph for example.

I am instantly thinking a badly blocked EGR valve. I have VCDS and it has thrown zero codes. I have checked the injection quantities and they’re all very good.

The other possibility is the MAF.

Ideally I want to prove which one is playing up before I take the EGR off or disconnect the MAF.

What’s the best course of action in VCDS

I forgot to add, it threw a code for the swirl flap actuator a few weeks ago. It hasn’t returned since I cleared it.

Not sure if related but I believe this engine has ridiculous (very high) compression and it takes a lot of force to turn the crankshaft.

So engine braking at it's finest. Normally i go neutral while going downhill to get better speed and economy than letting it roll on 6th gear.

If i roll down on 6th gear it barely speeds over ~100kmh while on neutral car reaches ~150kmh on the same slope i usually drive.

So there could not be a problem at all, just giving you another perspective. Of course plese keep looking into it and tell us what you found, If anything.

It does sound like the boost backs off and then goes again. As if it is being limited, halted, told to back off.

I am thinking of pulling the EGR and ASV off and giving them a good clean. Then I’ll test the EGR in VCDS.

Just wanted to see if anyone knew of a way I could actually pin point it using VCDS live data.

Just an update regarding this.

I took the EGR and throttle body off today and they were badly caked in carbon.

They both cleaned up well and I re installed them.

I forgot to plug back in the anti shudder valve / throttle body and the car pulled really well. Power was definitely back. It through an engine management light so I plugged it back in.

Car is down on power again now. The valve did move free-ish but I wouldn’t say it was smooth. Aren’t these involved more than just car on and off on the EA189 diesels? I believe the EGR has something to do with them partially closing?

A month on an a trip to a specialist later, nobody seems to be none the wiser.

The backing off has pretty much gone now, I haven’t experienced the push back sensation since fitting the new EGR.

There’s just a definite power loss now. A delay when I put my foot on to the boost actually coming through. With the A/C on, it seems even more sluggish.

Fuel pressure actual and specified seems fine.

Boost actual and specified are a few hundred mbar apart until about 2,200 RPM where they meet.

Injection quantities seem stable.

I’m at a bit of a loss. Heat definitely has an impact, warmer the engine worse the lag.