# Need Help - Rough Idle 98 Beetle



## Douglas C (Sep 21, 2005)

I would appreciate help with this one:
My 98 Beetle, 75,000 miles, 2.0L, 5 speed idles rough when I start it cold and continues to idle rough when warm. I would describe the condition as one cylinder not getting adequate ignition. Most predominate when the A/C is on. Runs great above 1100 RPM and
on the highway. I have replaced the plugs, (OE NGK's), and plug wires with OE VW. I have tried different brands of gas, and have run some fuel injector cleaner through it without improving the condition.
Check engine light does not come on.
Has anyone experienced this ?
Thank you.
Douglas C.


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## yellow99 (Jun 28, 2004)

*Re: Need Help - Rough Idle 98 Beetle (Douglas C)*

I'm experiencing it right now with my 99 auto 2.0L its got 72000kms. It's currently in the shop as we speak. It's happened to me twice in the past year and a half and both times they replaced the MAF sensor. I'm hoping it's not that again, because if it is I think they're too lazy to look around to see whats causing this problem. Well hopefully this helps! I'll let you know what happens when I get my car back tonight.


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## yellow99 (Jun 28, 2004)

*Re: Need Help - Rough Idle 98 Beetle (yellow99)*

Ok so now the guys at the dealer don't know what the problem could be. It goes in again next friday and they're going to look harder(I should have told him the engine was in the front!). Anyways as I know something I'll let you know!


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## jonboy72 (Apr 16, 2005)

*Re: Need Help - Rough Idle 98 Beetle (Douglas C)*

could either be the maf or a dirty throttle body, last time i had rough idle on mine i cleaned the throttle body and that solved it
thanks
J


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## AntiGravityHero (Sep 16, 2003)

*Re: Need Help - Rough Idle 98 Beetle (jonboy72)*

If you have a 98 and have never replaced your MAF (Mass Airflow Sensor), this would be my first suspect. Mine went at 40k.
The failures were so frequent that VW covered them under an extended warranty I believe... I am not sure that a car of this age qualifies, though...
I believe they run about $70, or you can try cleaning it with carb cleaner. You should also clean the throttle body as well (search the forums).


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## Lello GTI (Jul 9, 2004)

*Re: Need Help - Rough Idle 98 Beetle (AntiGravityHero)*

my fiance's has the same symtems (sp?) also.. hers is a 98 2.0.. getting ready to replace the plugs and works since it hasnt been done.. Its setting on roughly 75xxx as well.. might also check the MAF


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## Underdog (Oct 1, 2005)

I have the same problem with the 98 2.0 that I just bought as well... Drove excellent for the first day and then I woke up to rough Idle the next day.
Going on Service records. it has new plugs and wires just this past January and a Maf sensor replaced last summer.
I'm going to do some digging this afternoon and see what the condition of the throttle body, intake and prolly clean the Maf...
All this before I look in the direction of the Coil/Ignition module? Or does this sound unlikely?


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## yellow99 (Jun 28, 2004)

*Re: (Underdog)*

So I got my car back and once again it was the MAF Sensor, basically I will get mine replaced around every 10000Km's, as long as they still cover it under warranty!


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## Underdog (Oct 1, 2005)

*Re: (yellow99)*

Should this problem be sparatic? I can get the car to do it when I turn AC on and leave it in gear, and it does it enough to remind me its still a problem.
Would it still sound like a MAF issue?


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## BigBlockBug (Oct 7, 2003)

*Re: (Underdog)*

if it only happens under load as you describe that rules our ignition, MAF is Load based, it determines the ECUs interpretation of "Load" 
in short, yes, sounds like it may be your maf again


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## Underdog (Oct 1, 2005)

*Re: (BigBlockBug)*

Cleaned Maf that wasn't it... I was poking around and it finally threw a code, Missfire #1... there appeared to be an oily coating on the plug itself... cleaned and reintslled and all is well.... for now


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## BigBlockBug (Oct 7, 2003)

*Re: (Underdog)*

then you may want to check how much oil your PCV system is dumping down the intake tract, usually a culprit for a fouled plug


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## turbomustang (May 22, 2004)

Yup it sat for the night and has been doing the same idle issue this morning...
FWIW the oil was on the CONNECTION to the plug


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