N75/PCV - Lumpy Idle

[malaroo978]

Hi all,

I was hoping someone could help me out here. I've got the 1.4 TSI 170 in the GT Sport. Is the N75 valve the PCV? I havnt heard anyone actually link the two but im pretty sure the N75 is the PCV?

Reason being my lumpy idle is still around and seems to be getting worse, so I wanted to check the PCV as its a common fault and cause of lumpy idle (didnt realise this until another post yesterday!) Spark plugs are new and gaps are set correctly. I'm not sure about the coil packs, one has been visually gauged on the plastic by a previous garage but besides that look ok. How can I check the N75/PCV? I pulled out the dipstick with the engine running and it went rougher then went smoother when I replaced it (still got kind of a misfire). I havn't got a fault code reader so don't know if its misfire etc. (got one in the post - cant afford VCDS :()

Any other suggestions for excessively lumpy idle? Cold idle (1200RPM) is even worse! I know its not the 2.0TSI engine but hoping you guys may be able to help.

Got warranty until the 21/01/2012! Going to buy the extended warranty though so should still be ok. Been into VW and they just said they couldnt find any codes and maybe replace the spark plugs (even though they were brand new!)

[56OctyVRS]

The pcv purely deals with crankcase pressure and the n75 deals with regulating boost pressure. They are two seperate valves. I fitted new plugs in my car and after 2 months my car developed a misfire. I changed the plugs and the misfire was gone. I was suprised that a plug went after about 1000 miles. I would try a new set of plugs from a different batch and see how it goes. At least you will know and if it isnt the plugs then you will some spare ones or be able to sell them onto someone on here.

[malaroo978]

Ah right, so it is different then. I just know the N75 is a common fault on the 1.4TSI. Does anyone know where I can find the PCV on the 1.4TSI?

Yer I got a set from Blade on here that I'm going to set to the correct gap and try to see if that works. It seems to have had the misfire feeling all along, the garage changed the spark plugs when I bought the car (november) to solve a jerky acceleration issue. Been misfiring on idle since then (and before I think) but worth trying new plugs.

I'm going to push VW to look into it more, I had a different 1.4TSI and I dont remember it doing this. But I can't remember what a standard lumpy idle is anymore. I'm just trying to rule things out along the way, hence the PCV thing.