vwalton

My 2000 TT 1.8 has a weird idle problem: after it warms up (anywhere from 10 to 20 minutes after starting) the idle goes to 1,600 then varies from there to about 1,800 every two seconds or so. And it's throwing a P0507 check code.

My 3rd-party mechanic replaced the throttle body twice with no result. I took it to our local dealer, and he has replaced the PCV system, another throttle body, mass air flow sensor, EGR valve, checked every hose for leaks, and clamped off every valve. They've had the car over 3 weeks now and he's completely stumped. We're waiting for a factory rep to come out and look at it.

One thing he noticed that he's never seen before was when he had some of the hoses clamped suddenly the idle went to normal, but it started burning massive quantities of oil and smoked up the whole shop. I don't know if this is relevant or not, just throwing it in there.

The car drives perfectly normally.

If anyone out there has an idea what we should check next, please chime in. I'm really starting to miss my car!

vwalton

Oh come on! All the brilliant people on this forum and you can't make suggestions on a high-idle problem?

MosTT

I have 2001 quattro 225hp. Our cars have two sets of gremlins, electrical and vaccum. Two places that are likely from my own repairs 1) the main portion of the exaust gas recirculation has a 3-4 inch plastic pipe from the bottom front of the engine that is likely deteriorated it also connects via various hoses to the pcv valve hose. Many other hose connections have a type of hose that essentially melts away from the inside and leaks vaccum. There is a post with photos in FAQ that describes it. 2) At the top of the same system under the air induction system is a plastic pipe like a trumbone or trumpet that also has vaccum hoses running from it. Mine had a crack in it. First I just taped it using duct and electrical tape as the replacement it tricky. Eventually I had to replace it. All parts will be much less on line than from the dealer. The turbo induction system will go out soon too so get one of the after market replacments like semco, etc. Hope this helps, sorry I dont know the names for all the parts.

vwalton

I'll run this by my mechanic - thanks, it may save me a ton of money. (They want to replace the intake manifold, and I think that's not indicated yet.)

Sorry, all, for the snarky tone of my second post. I'd delete it if there were some way. It was meant to be a compliment and didn't end up sounding like one ...

MosTT

It seems they have already charged you for ineffective repairs. It might be best to go to a different place, unless your present mechanic will give you some credits for the work already done. those parts can be hard to get too so the labor will be the biggrest cost. Hope it works out for you.

vwalton

Well now they want to replace the ECU - for $1,300. "It has to be that because we've eliminated every other possiblity." Well, in my book that's a pretty thin thread to hang that kind of charge on! I'm not saying it's the ECU, but there's no evidence that it is. And if it crosses the parts counter, I've bought it. I'd rather buy something used, or at least 3rd-party - any ideas on where I could go?

AudiMick

I would go for ECU also, but I think reflashing it might be a better idea. Unfortunately only the dealer can do that.

vwalton

[QUOTE=vwalton;23997035 I'm not saying it's the ECU, but there's no evidence that it is. [/QUOTE]

I meant to say "I'm not saying it's not the ECU ..."

(I wonder why you can't edit your own posts here?)

AudiMick

Something to do with your status here probably, we old timers are able to edit.

vwalton

Well the way things are going, I'll probably be able to edit before this thread ends and I get my car back ...