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mk4 1.8t 2000 please help !!!!!

431 Views 5 Replies 3 Participants Last post by  chixon9291
hi all, i currently got an intermittant problem that occurs maybe twice a week, when i 1st start the car whatever time of they day it doesnt idle properly the rev counter goes up and down between 300 and 600 revs and the car sounds like its missing or gonn stall, like i said this isnt the case all the time, i have recently done a oil change and plug change, its really starting to bug me now as i havent a clue why its doin it, hope ya can help cheers alex
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dirty Throttle body, maf or a vac leak. my monies on the TB or maf
ok so will it just need cleaning? how could i tell if theres a vac leak thanks for the quick reply alex
does it idle fine if you keep the revs up with the throttle/ if it does then i would also place money on a dirty throttle cody. yes you can just clean it use some degreaser
both maf a TB can be cleaned. your better off buying a new maf tho if im honest as it will just be gay again before you know it. TB is held on with 4 torx bolts. 1 bolt is a bit of a pig to get to but its just fiddly. remove and cain it wiht brake cleaner etc. I powerflowed mine will all my 1.8ts, mirror finish on the inside.

Depending on the age of the car the TB will need resetting. if you have cabled Throttle just leave the battery off for 20 mins and reconnect. the ECU will work out the rest. It will prob tick over at about 1000 rpm for 20 miles or so till the ECU sorts it. I have used this on both AGU and aeb 1.8ts i have had and it works fine.

The newer lumps you will need VAGCOM to reset it. I would suggest you scan it with VAGCOM anyway as its easier to get a correct diagnostic with that than over the interwebings. as for the vac leak, check the pipe under inlet manifold near dip stick. they always split.
yea only happens wen i leave to idle on it own, cheers for your help i will give it a clean and hopefully the problem goes
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