My car has started to idle funny again :(

[Overseer]

older members may remember my MOT hassles late last year!

right now its still dropping back to idle around 900 ok.. but the revs are a bit unstable.. and its being slow/poor at falling back to idle.. sometimes it falls, sometimes not..? it definitely feels like something is sticking and/or clogged up again

oh and if i accelerate harshly (as if! ) the throttle revs sometimes seems to stick..



somehow these problems got fixed by doing some of the below (in a short space of time..) so here's my checklist.. i'll report back.. after each attempt at trying to do something about it!

since the last problems it's also had a nice service.. new plugs, filters etc etc.. and been running fine for around about 4 months now.


- Lube throttle related springs etc etc? (didnt do this last time afaik)

- Check for vacuum leaks (this was the cause of 2 faults last time, both due to bodges by previous owner)

- Check/Clean the ISV (did this last time.. didn't help but its an easy job) ncie pictorial guide for those interested >> http://www.clubgti.co.uk/forum/forum_posts.asp?TID=3114&PN=1

- Clean the Throttle Body? (pretty simple too..)

- Give electrical contacts a squirt of WD40

[Overseer]

'course if anyone has any other ideas or questions.. i'm open to suggestions!

[Overseer]

even though i did more reading around and most things seem to point to the ISV i still cleaned out the throttle body tonight and lubed the throttle (it was ok though really)

did check for leaks too.. but thats pretty hard to do.

while being sat the car, door open, bonnet up.. at points where the car wasnt settled back to idle i can hear a faint pulsed "click click click" kind of in time with the variations in the engine note.

so i'm pretty sure its the ISV now..

tomorrow i'm gonna get the ISV out and give it a good clean/soak in carb cleaner.. see how it goes.. last time it was given a quick flush.. this time i'll let it soak for a couple hours before refitting it.

[888v]

cleaned my isv about 3 times and it stopped for a while each time, then started again so i decided to get one from a breakers for a measly 25 quid. all that hassle sorted 4 very little cash

[Overseer]

hmm ? so u think i'm on ball with this one now? last time there were really 2 problems.. fixing the ISV last time may have only been part of it..since there were 2 vacuum leaks..



well if this cures it i might call around for one..

buying new would be nice.. but 175 quid odd from VW??

[888v]

you'd be a fool to buy a new one, yeah new looks better but the chances are you will only ever replace the ISV once in the cars lifetime so the majority of second hand ones are just as good.
just clean it up???!! definitely worth a try though i reckon matey

[Overseer]

shame its a sealed unit.. bit of a pain to clean up..

def worth a go from a breakers if they're going that cheap!

[Overseer]

before work this morning i spent 10 mins taking the ISV off.. and doing the best i could filling it with carb cleaner and shaking it.. after putting it back on the car is behaving better again.. its still not perfect..

time to call some scrappies i think

[Overseer]

called VW first to try get the part number.. they wouldnt let me have it..

VW prices.. 233.52 and 2.20 for the grommet that goes into the manifold..

breaker i tried tells me the ISV part number is 037 986 457D


noticed this morning i'm pretty low on oil and since vw are next door i'm gonna get the grommet too since the one that was there isnt in very good condition and could be causing a vacuum leak..

tonight i'm gonna soak the ISV for a few hours and give it a better cleaning up

[Overseer]

driving home tonight it didn't seem quite so good.. but maybe i'm watching it too cloesly.. i topped up the oil and have given the ISV another clean up tonight. so we'll see...

btw.. i find it odd this seems to have coincided with the change in weather here to being more temperate...