As the title suggests, I'm getting a very rough idle every now and then. It only happens first thing in the morning and It's not every time though. The issue is when the engine starts all seems fine, it idles fine until I select a gear. Then the rev counter bounces all over the place and if you take your foot off the brake kangaroo hoping starts. To sort it all out I just move it out of gear and give it some throttle.
Anyone else had this before or have ideas?
Thanks,
Garry
Very Rough Idle - cold start
Very Rough Idle - cold start
R18 GTX Estate > Saphire 2.0i Ghia > R19 16v > Vectra V6 SRi > M3 > RS6 Avant
Re: Very Rough Idle - cold start
Sounds like an air leak. Or maybe a bad MAF. What are your trim values like?
Maybe a diff coolant temp sender.
Maybe a diff coolant temp sender.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
Re: Very Rough Idle - cold start
I was thinking MAF or may throttle potentiometer. I've not checked the trim values, as it's not all the time. I'll do a few cold starts with the laptop plugged in and see what data I can read off.
Wouldn't an air leak cause it to happen both hot and cold?
Hows the coolant temp sender likely to cause this?
Wouldn't an air leak cause it to happen both hot and cold?
Hows the coolant temp sender likely to cause this?
R18 GTX Estate > Saphire 2.0i Ghia > R19 16v > Vectra V6 SRi > M3 > RS6 Avant
Re: Very Rough Idle - cold start
Incoherent temp values will affect the fuelling. It adjusts the injector times based on the engine temps.
I don't think it's the throttle. It has a redundancy and would bring up an EPC warning if there was an incoherence.
If there's a leak it may affect the idle more or less depending on other factors.
Any codes stored?
I don't think it's the throttle. It has a redundancy and would bring up an EPC warning if there was an incoherence.
If there's a leak it may affect the idle more or less depending on other factors.
Any codes stored?
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
///M3 E46 | XC90 (V8, natch) | Passat GTE | RR Classic V8 flapper
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."
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