# Mk2 jetta ruff idle 8v



## MeinGLI (Nov 5, 2008)

Any ideas on this guys, i need this fixed asap


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## ps2375 (Aug 13, 2003)

*Re: Mk2 jetta ruff idle 8v (MeinGLI)*

bad plugs.


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## epjetta (Sep 19, 2006)

*Re: Mk2 jetta ruff idle 8v (MeinGLI)*

has it had a tune up at all?


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## ps2375 (Aug 13, 2003)

*Re: Mk2 jetta ruff idle 8v (epjetta)*

Seems he just needs ideas, more info would help, but some on here can read minds, I guess.


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## MeinGLI (Nov 5, 2008)

*Re: Mk2 jetta ruff idle 8v (ps2375)*

Yea, I just installed new plugs,cap,wires,rooter and i still got the same problem. Idk im lost on this one...


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## ps2375 (Aug 13, 2003)

*Re: Mk2 jetta ruff idle 8v (MeinGLI)*

What do you mean by a "ruff idle"? What is the idle rpm? Does the roughness continue off idle and if so , up to what rpm? ave you puled the plugs to check for discoloration? Have you checked for vacuum leaks, very possible since this is a CIS motor. Other than changing parts, have you done any checks and/or adjustments?


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## MeinGLI (Nov 5, 2008)

*Re: Mk2 jetta ruff idle 8v (ps2375)*

It bogs down when its at idle the rpm it about 1grand till it almost stalls out and then it comes back up. It does it over and over again. Yes it contines off idle also up to about 3grand. The plugs are new about 500 miles on them. No i have not looked for vacuum leaks yet but i will now. The timing belt and reg belts have been changed about 1000 miles ago and thats it nothing else done to it...












_Modified by MeinGLI at 8:43 PM 12-20-2008_


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## umeng2002 (Jul 9, 2003)

*Re: Mk2 jetta ruff idle 8v (MeinGLI)*

If the idle bounces around, the idle control valve is dirty. Use some throttle body cleaner and clean it out.
If cleaning doesn't work, it might be a vacuum leak or it's just time for a new valve.


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## MeinGLI (Nov 5, 2008)

*Re: Mk2 jetta ruff idle 8v (umeng2002)*

Ok, Im not sure were the idle control valve is? Can you point me in the direction were it is? Im new to the mk2 world...


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## umeng2002 (Jul 9, 2003)

*Re: Mk2 jetta ruff idle 8v (MeinGLI)*

It's that big cylinder thing with hoses coming out of it above the the valve cover just left of the the bif round black thing on the valve cover.


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## MeinGLI (Nov 5, 2008)

Ok thanks...


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## MKhamiII (Apr 15, 2008)

*Re: (MeinGLI)*

im having the exact same problem. spikes to 3 grand if left to its own devices. i just tap the pedal until it like knocks it back to the right place. seems to work. but im going to try cleaning the idle control valve tomorrow.
heres a picture







hope that works


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## vwaro725 (May 29, 2007)

*Re: (MKhamiII)*

i had the same problem with my old 8v my injector o rings were shott air was leaking in and raising nd lowering the idle sometime to 1500 other to 3000 take some carb cleaner nd spray it on the injectors by the orings if the idle spikes you got a leak


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## Twin Weber (Aug 10, 2004)

Take you ISV and your Throtle body off and clean them with throtlebody cleaner.. It solved my problem right away.. Reason for cleaning the throtle body is the butterfly valves inside git sticky and some times get stuck shut...


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## MK2SnowPilot (Sep 8, 2005)

*Re: (Twin Weber)*

Don't forget the switch on the underside of the Throttlebody. It's only purpose is the tell the ECU that the throttleplate is fully closed. It loses it's adjustment over time and needs to me re-adusted so that it clicks as the TB closes. with the car off just operate the throttle by hand and listen for the click.
Without that switch working your car will be constantly hunting for idle. An easy test is to unplug the wiring to that switch and jump the two wires. If the idle improves with it jumped then your problem is the switch adjustment.
Oh and the wiring to that switch likes to break over time too.


_Modified by MK2SnowPilot at 12:29 PM 1-5-2009_


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## MeinGLI (Nov 5, 2008)

Thanks for your help guys, im goin to try all these things...


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## vwbeaner (Jun 4, 2007)

*Re: (MeinGLI)*

Check your idle screw also, sometimes the seal goes bad, if it does you have to buy the whole screw from vw or put some teflon tape on the threads. I had to adjust mine the other day because the idle was bouncing and my car whould shut off when I pushed the clutch in after a few mins on the highway.


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## MeinGLI (Nov 5, 2008)

Ok thanks will do...


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## MKhamiII (Apr 15, 2008)

*Re: (MeinGLI)*

ever find any resolve to this?


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## hankolerd (May 31, 2006)

*Re: (vw******)*

yeah, after a while those idle screw seals will fail. One day i was cruising along and I heard a little ting on the bottom of my car. I figured it was a rock or a small piece of metal(didn't think idle screw) when I went to take a turn I pushed down the clutch and the car died. haha good times.
I had what sounds like the same problem last summer, ended up being the seals around my injectors, one of them was tore all the way through and the others in rough shape.
good luck.


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