I'm trying to troubleshoot a niggle with my 2006 Octavia VRS, that only happens when starting the car after it's already warm. I'll try get a decent video/audio of the symptoms as soon as I can, but wondered/hoped if anyone would recognise the problem from a brief description.

• Octavia VRS 2.0 TFSI / MK2 2006 / EA113 / BWA / Manual / 123k miles / Stage 1 remap.

• 2-3 second stumble/chugging sound when engine is started whilst already being warm/recently used.

• Sounds like the engine is either getting too much or not enough of something, before sorting itself out and settling.

• Normal cold starts are generally fine.

• Normal running/driving is fine and still pulls strongly.

• Symptoms first occurred in May 2026 - the first day of the really hot weather (I'd spent around four hours throughout the day driving mostly short journeys, some fairly "spirited" driving).

• No relevant error codes.

• Work already done in the last 12 months (some required, some preventative maintenance): cam belt and water pump, four new injectors, cam follower, PCV, intake carbon clean, spark plugs, coil packs, stage 1 remap and diverter valve (GFB DV+), new battery, EVAP valve checked and clear, vacuum system passed a smoke test.

• Other minor niggles: throttle lift-off/overrun feels a little rough/jerky sometimes; temp gauge sometimes drops to 70-80 on motorway journeys.

My local garage have had the car in twice for diagnostics and couldn't identify the problem. Had it earlier this week, after I asked them to check for the thermostat sticking/failing, to double-check the EVAP valve, and to check that the GFB DV+ diverter valve wasn't sticking (all suggestions from forum research, and ChatGPT/Gemini), but the garage couldn't find anything obviously wrong. I was very tempted to get them to replace the thermostat and EVAP/N80 valve anyway, since they're fairly inexpensive (parts and labour), but they advised that unless I want a full engine rebuild, it's probably best to stop chasing little niggles if the car generally runs fine.

A separate VW/Skoda/Audi specialist also had the car for a week (a couple of months ago, to replace the fuel injectors and perform a carbon clean/walnut blast) and couldn't replicate the chugging sound either. Presumably because they didn't restart the car after it was already warm. They also mentioned that the intake manifold motor/actuator was sticking a bit, so they took it out, cleaned it up, lubricated, etc and put it back in (doing whatever reset/coding was necessary too), and said to keep an eye on any related error codes popping back up. So far, nothing.

Does this startup chugging sound familiar to anyone?

I'm trying to not just throw parts at it and hope for the best, as I've spent enough already. I'd just like to get these last few niggles sorted out, then I can relax a bit - until the next time, haha!

Thanks in advance. I'm very much not a mechanic - just stuff I've read online. Any help is greatly appreciated.

Read online that it might be high pressure fuel pump not keeping pressure when engine off when warm. Pressure dropping due to heat/failure when engine off and takes 2-3secs to get to full pressure again. Think you can monitor pressure with vcds. Could also be sticking diverter valve.(GFB) DV+ According to google its something to do with brass piston in alloy casing that can stick when hot due to metals expanding at different rates. If it was installed dry it may need lubricating with engine oil or HT silicone.?? (acording to google so pinch of salt may be required)

Alasdair