1.8t mk4 golf idle

[Deejay123]

Hi was wondering if anyone could help

I have a 2000 VW golf mk4 1.8t 20v high millage on 170k
I recently acquired this car and since I have nothing but problems

Below is what i have already done to the car i will then explain what is still wrong with it

Coolant flush
New expansion bottle + cap
New oil
Oil filter
Spark plugs
Coil packs
Inner rocker gasket and outer rocker gasket

So basically the car as soon as I got it developed a really bad hunting type idle where it would go from 900rpm down to 500 then back up again plus the exhaust was spitting abit of oil
Took the plugs out and noticed they were drenched in oil so clearly oil was getting in the spark plugs wells so that's when I decided to changed the rocker gaskets they've been changed and new plugs went in and original coil packs stayed it ran fine after this for about 2 weeks when the EML came on (was never on before) and it starting idling rough again not as bad as the first time so thought ahh probably a dirty throttle body so I took that off and yes it was dirty but not as dirty as I thought but either way I cleaned in properly and got it back on but it made no difference (I didn't get this realigned as I've just found out you have to once removing?)

I then changed the coil packs with a £100 set there was no oil on them and checked the plugs and they look good
EML has gone out but the car still idles rough it idles at about 780-800rpm and will flutter 100rpms up or down
Engine shakes on the mounts enough to see it and feel it when in the car and also hear it no oil is being lost and no coolant either no smoke it's literally just the idle took it for a good run and I'm not getting poor mpg I got 36mpg on a 20 mile motor way run sitting at 75-80mph
I dont feel like I'm losing power as car still picks up strong and goes well through the gears

I'm under the assumption that I have a possible vacuum leak ? (Cant hear anything on idle however)
Or possibly a crappy plug that I changed ?

On start up the SAI kicks in for about a minute or so and it is rather loud suggesting this could be knackered? But it does go off after a minute and as to my l knowledge it's not in use after that anyway

If any one could shed some light I'd be much appreciated starting to do my nut in now thanks guys
Deejay

[Goldie.88]

Hi Deejay,

Hopefully you've had better luck with this now. I've just done the same with my 1.8t Passat, was finding idle was rough and there were some engine codes on misfire at low RPM. Youtube said try the PCV system and sure enough the valve was broken. I'm just waiting on the final parts to put it back together, will let you know if that was the fix.

Goldie.88

[Scott K]

Hi Deejay,

I have moved this to the correct section so you will get some replies.