Passat R36 Idling Rough

[JRusit]

Hi Everyone

My R36 is idling a bit rough and when I accelerate the car has a little bit of a lag. I've tried the following to no avail.

- Throttle body clean with Three Bond Engine Conditioner
- TPS cleaned
- Spark Plugs changed
- Liqui Moly Fuel System Cleaner put in a tank of petrol

Has anyone else experienced this before? Any ideas of what is causing it?

Thanks for any help you can give.

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[Umai Naa!!]

Dead coil pack?
Dead injector?

Have you scanned it for codes?

[JRusit]

Dead coil pack?
Dead injector?

Have you scanned it for codes?

No it's booked in on Monday to get scanned. My engine check light isn't on so does that mean there wouldn't be an error code?

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[Umai Naa!!]

It may have stored a code or two.

Some scan tools will also log a missfire counter, per cylinder which will help narrow it down.

[JRusit]

It may have stored a code or two.

Some scan tools will also log a missfire counter, per cylinder which will help narrow it down.

Ah ok. Is there a way to test the coils and fuel injectors without having a code scanner?

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[Umai Naa!!]

Well that would require other test equipment like an oscilliscope, noid lights, and fuel pressure guages.

Plus you'd still need the scan tool to reset the ECU, as it's programmed to cut injectors when missfires are detected.

[JRusit]

Well that would require other test equipment like an oscilliscope, noid lights, and fuel pressure guages.

Plus you'd still need the scan tool to reset the ECU, as it's programmed to cut injectors when missfires are detected.

Ok no worries. I might just leave it to the experts on Monday. Thanks for the input.

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[snerlo]

Hope you get it sorted mate.

[JRusit]

Turns out I need a new PCV valve. That's something I didn't even think about.

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[MatC]

mine does that slightly after prolonged idle periods.. a little stab of the throttle it goes away - i'm leaning towards carbon build up,

shows a missfire - but that could be carbon on a plug, a dead plug (replaced 10 months ago), or a coil pack. it shows an O2 sensor fault on my OBD11, but that would be due to unburnt fuel causing an odd reading.