Idle Issues

[DriverFound.]

Hey guys,

I got a MK4 1.8T Jetta and I've been noticing recently my idle has been fluctuating. After some googling and a cup of coffee or so I discovered it could be my TB needs cleaning, boost leak?, bad combi valve. Also, I should hook up vagcom(hopefully I could get someone to help me out with that) and take a look at my MAF and O2 sensors in real time. Of these suggestions which one do you think is most accurate? Ive also noticed a ticking sound just slightly over top the sound of my injectors, I guess it may be coming from the lower part of the engine but that is only a guess...any help would be greatly appreciated. This weekend I had planned on installing new upper and lower PCV hoses, as well as clean the TB.

Thanks,

Chris

[CGY_GTI]

Re: Idle Issues

It could be a vacuum leak. My old Jetta had a vacuum leak at one point and the idle was jumping around like crazy before I got the hoses replaced. At one point, it got so bad that it wouldn't even hold an idle and it would just die unless I pressed the gas a little and kept it over ~1200RPMs

[DriverFound.]

Re: Idle Issues

Thanks for the quick response! This weekend when I do the PCV hoses that could be the fix, they are possibly the worst hoses on the car, and if they do spring a leak they get covered in blow by and could very well be the culprit.

[MechEngg]

Re: Idle Issues

My lower T hose has been broken for 2 months now, no idle issues what so ever. I can however only boost to 12psi instead of the regular 22psi that i used to. But still a steady idle

[DriverFound.]

Re: Idle Issues

My lower T hose has been broken for 2 months now, no idle issues what so ever. I can however only boost to 12psi instead of the regular 22psi that i used to. But still a steady idle

Haha oh damn! I will see if cleaning the Throttle body helps this weekend, if not I imagine the O2 or MAF have gone sour.

[tirerub]

Re: Idle Issues

You'll also wanna use vagcom to do a throttle body alignment if your taking the throttle body off. You can unplug your maf and see if there's any change aswell if it Improves Slightly you may have a bad maf
The best way for finding boost leaks is with a pressure tester on the tip and a air compressor