rough idle/misfire without fault code

[generalen15]

hi, i have got some problem with my golf 5 gti 2008, that started to have issues a week ago, first fault code that came up was P2187 (system too lean at idle,bank 1) and after a swapped spark plugs while i wait for my new pcv part it change to p2279 (intake air system leak) and now with the new pcv that a testing by blowing and sucking it doesnt leak like my old one did, but it still running rough only at idle as soon as i give gas it goes away and today i cruised at 160kmh for 90km without issues. and my injector only ran 5000km since service with good numbers before and after the service on them. anyone have had problem with coils that doesnt work right only at idle and doesnt throw any fault codes?

[mjmallia]

Sounds like the oil pressure control rings on the cam actuator to me. Does it sound better when the revs are raised up from idle?

[generalen15]

Sounds like the oil pressure control rings on the cam actuator to me. Does it sound better when the revs are raised up from idle?

the 3 oil rings i change 1.5 years ago same time as the timing chain. the issue is on only idle just 1% gas will make it run perfect, the cam adjustment and phase position are always good when looking at live data. and if it was the vvt it would throw a code fast when i was going 160kmh cruise for 90km, but zero fault codes.

[ZoliWorks]

Open VCDS and look for misfires. See which cylinders are doing it and how often. Measuring Blocks 14-15-16

[generalen15]

Open VCDS and look for misfires. See which cylinders are doing it and how often. Measuring Blocks 14-15-16

will take a look there, but shouldnt it give misfire code if it counting them?

[mjmallia]

Yes and no.

The rings I mentioned gave a lumpy idle that sounded like a misfire, but the car was not misfiring due to a lack of oil pressure to the cam phaser not being able to manage it correctly.

I also had a misfire on cly4 due to carbon build up but still that was not registered as an error code but could see the count and hear it also.

[generalen15]

UPDATE! i did check live data on misfires and it misfired alot on cyl 2 and very few on cyl 3 so i tried swaping plugs and coil but with no progress so my only thought was ''well the new services injector must be bad'' on cyl 2 and cyl 3 so i was gonna try to swap them with 2 of my old ones that i know is in working condition but when i remove the intake i notice cyl 2 runner flap was very melted so that must be the problem, so now i just need to order a working manifold and see if the problem will be fixed after that...

[ZoliWorks]

UPDATE! i did check live data on misfires and it misfired alot on cyl 2 and very few on cyl 3 so i tried swaping plugs and coil but with no progress so my only thought was ''well the new services injector must be bad'' on cyl 2 and cyl 3 so i was gonna try to swap them with 2 of my old ones that i know is in working condition but when i remove the intake i notice cyl 2 runner flap was very melted so that must be the problem, so now i just need to order a working manifold and see if the problem will be fixed after that...

Honestly at this point just get one of those ebay/aliexpress runner flap delete kits and re-map your car for an RF delete. If you dont remap, you'll have cold start misfires.

Good thing you caught it in time tho. If the engine sucked it in, it would have been very bad.

Still, I would do a compression and leakdown test on that specific cylinder. I have a hard time accepting that only cyl 2 got melted while the rest look fine. Maybe a valve isnt closing properly and exhaust gasses bypass back into the intake? Or worn out/pitted camshaft lobes are messing with the valve making it not seal properly.

[generalen15]

UPDATE! i did check live data on misfires and it misfired alot on cyl 2 and very few on cyl 3 so i tried swaping plugs and coil but with no progress so my only thought was ''well the new services injector must be bad'' on cyl 2 and cyl 3 so i was gonna try to swap them with 2 of my old ones that i know is in working condition but when i remove the intake i notice cyl 2 runner flap was very melted so that must be the problem, so now i just need to order a working manifold and see if the problem will be fixed after that...


Honestly at this point just get one of those ebay/aliexpress runner flap delete kits and re-map your car for an RF delete. If you dont remap, you'll have cold start misfires.

Good thing you caught it in time tho. If the engine sucked it in, it would have been very bad.

Still, I would do a compression and leakdown test on that specific cylinder. I have a hard time accepting that only cyl 2 got melted while the rest look fine. Maybe a valve isnt closing properly and exhaust gasses bypass back into the intake? Or worn out/pitted camshaft lobes are messing with the valve making it not seal properly.

yes, the plan is to check the compression and build up on cyl 2 and i will do flap delete on the other intake that i will buy. maybe a dumb question ticking lifter on these engines cant cause exhaust gases in intake right? cause i have 1 or 2 ticking lifter that im was gonna take care of in like 2-3 weeks when my colleague is back at work, and i can mention that the day all this happend i was crusing at 160kmh and the car started misfire like crazy on cyl 2 and i had to drive for like 5-10 min at 80 kmh behind a truck until nearest truckstop, couldnt that overheat and melt the plastic?

[hcmzah]

what causes these to melt, does anyone know?