At idle my 1.05 mk3 runs at 1000rpm but every 15 seconds or so it drops to about 800 rpm for a split second. It doesnt stall but sometimes sounds as if it wants to.

Basically its just annoying but is this due to the throttle body needing a clean and if I do this and carefully wipe around the butterfly area will I have to have the ECU reset.

Cheers for advice

check the vacuum pipes for air leaks, throttle bodies on the mk3 are pretty reliable, but a clean wouldnt hurt it! and no you wont have to reset the ecu, that only applies to later polos. do a search too cos that might unearth a few ideas!

check the vacuum pipes for air leaks, throttle bodies on the mk3 are pretty reliable, but a clean wouldnt hurt it! and no you wont have to reset the ecu, that only applies to later polos. do a search too cos that might unearth a few ideas!

Cheers for reply

The vacuum pipe underneath the air filter housing has a hole in it about the size of pea. This could be the culprit.

check the vacuum pipes for air leaks,

Cheers for reply

The vacuum pipe underneath the air filter housing has a hole in it about the size of pea. This could be the culprit.

Quite possibly. Mine had a big gash in it, and this created the same symptoms.

A vacuum pipe with a hole the size of a pea? That sounds like you've found the oil breather. OK, so it's an air leak but it's not the other side of the throttle body, so shouldn't make much difference?

Yeah, you wouldn't think so. But mine had a hole in it a few inches from the end of the pipe which is attached to the cam cover. The idle would quickly dip to from 900rpm to 500rpm ever few sends when idling and the only thing which stopped it was a new breather pipe (the whole lot was replaced). Nothing else ever made any difference.

Fair enough then. I've got a fairly poor idle at the moment but I thought it might have had something to do with my new (second hand) injector that I haven't ran any injector cleaner through. The hose is in a shocking state, maybe I should replace it.

My MK4 does exactly this and a TB clean didnt make any difference. Is it a hard/expensive job to do?

Yeah my oil breather hose ( the one that attaches to the cam cover) is in a shockin state. Its literally like putty, you can cut a bit off and squidge it up into a ball.

Where is the best place to get these replaced - can you just use any type of pipe and a hose clip.

Cheers

can you just use any type of pipe and a hose clip.

If you've got the time you could but you can still get them from VAG.