New problem on our 1.6SR. Done 120k miles. Well serviced. Have had all the cracked air pipes new, cleaned the MAF, had new coil pack, new plug leads, new plugs and it still does the eratis idle thing , but that is not the real problem. Twice now it has burnt out either 3rd or 4th cyl, plugs or leads.....starts running like a tractor with smoke everywhere. VW and another specialist have checked compression and all good. Last fix was the new coil pack, another set of leads and another set of plugs!! Any ideas? ECU problem?? The last fix lasted about 100 miles.
Is it fouling up with oil or fuel? You say the compression check is ok so unlikely to be piston blow by, if the plugs are sooting up it could be an injector fault.
Compression check was done about 600 miles ago when it 1st did the same thing. Plugs are oiled I believe more so on 3rd or 4th. Whichever cylinder has the missfire has the oiled / knackered plug. 1st time was the 3rd cyl, 2nd time was the 4th? This time not sure as waiting to get the car recovered. (VAGcom shows the misfire when running.)
Finally Beetle is fixed. Full engine rebuild. Turns out problem was 3rd piston lower oil ring was in peices. All miss running problems have gone. 120k what a load of crap!! 1800 euro's it cost just for the rebuild to be done properly.
