Polo rough idle on cold start, idle stumble, etc

[gavs]

After driving home this afternoon with the new tank of fuel I didn't notice the issue at all, but I think you may be spot on about the traffic scenario, every morning I deal with bull**** traffic, and I notice it most then, driving home its not so bad..

This afternoon it behaved, so its quite possibly the fans kicking in!

I have noticed it behaves differently when I revert back to the stock tune, I might try the APR 95 octane tune and see how it goes, it really doesn't like the shell 98 I get at my local servo on the 98 tune.

If the fans kicking in are making the idle stumble that much, I'd be looking at either your alternator or hopefully just your battery is on it's way out.

One thing that the 6R has for it's models is that on cold starts, it opens the throttle and dumps a lot more fuel into the system to get the oxygen sensors warmed up and operating properley as quickly as possible, resulting in loud,rough stummbling idle for the first 90 secs of operation and lumpy idle until the temps all hit around 60 degrees. Is this something that could be the same as the cold start issues some of you are mentioning? I'm not that familiar with the 9n engine's progression...

[VWindahouse]

It's after the fans stop Gav. The revs seem to drop lower than when the fans were off by 100 or so rpm creating a lumpy idle. Only seems to happen in cooler weather though.

[h100vw]

Going to order a cable off ebay, any specific one people recommend?

Any old cable should be ok for using lemmiwinks. Don't expect proper VCDS capability though.

Mitchr these are 9N GTI idle issues, not sure if you had noted that. The 6R is a different ECU type amongst other things.

Gavin

[flat6]

Can confirm the issue is caused by crap fuel using the APR 98octane Tune,

Filled up last week with United 100 octane, didn't experience any issues all week

Just filled up today with Shell 98, bam, rough idle, rougher to drive, however switched the tune to the APR 95 Octane and its ok, Got a feeling were not really getting 98 octane fuel.

Anyone else noticing this with Shell 98 at the moment?

Edit: after further testing, even on stock tune its still stuttering, bad batch for sure, dodgy bastards

[noone]

I try to only use BP98, seems to be the best for performance when I tried a few, read similar from others.

Would it be worth replacing the fuel filter now? Might be worth using a injector cleaner additive for peace of mind.

[Blitzen]

Can confirm the issue is caused by crap fuel using the APR 98octane Tune,

Filled up last week with United 100 octane, didn't experience any issues all week

Just filled up today with Shell 98, bam, rough idle, rougher to drive, however switched the tune to the APR 95 Octane and its ok, Got a feeling were not really getting 98 octane fuel.

Anyone else noticing this with Shell 98 at the moment?

Edit: after further testing, even on stock tune its still stuttering, bad batch for sure, dodgy bastards

Its funny you say that, but I started noticing it after I got rid of my BP fuel card and using Shell 98... I might throw in a tank of BP Ultimate
When I fill up and see if it still does it.