Totally Random Idle, Kangarooing Etc Etc

[Pete C 0]

Just bought a Ph1 309 GTI. Does the usual hunting/cutting out from stone cold, I'm used to that. But then as it's warming up it does the weirdest things; idles at 1700rpm and then for no apparent reason drops to 700rpm, nearly or actually cutting out before being really high again at the next junction.

 

When warm, most of the time it idles at 1100/1200rpm, with the occasional 2000rpm thrown in. It also feels sluggish on full throttle compared to my last 309 Goodwood.

 

The weirdest thing it does is most of the time when I reverse, say round a corner or just parking, when I take my foot off the accelerator after having reversed to let the revs drop to idle, it'll hold it at 2000, maybe even 2500rpm, before dropping down if I blip the throttle a few times. This happens far too often to be a coincidence, it's got to be something to do with reversing, but I struggle to think what!?

 

As if all that weren't enough, it likes to try to cut out/kangaroo when I'm trying to pull away, and sometimes when I change from 1st/2nd.

 

I think I must have been lucky in the past, I've never had an XU9 that ran this badly and have therefore never had to fix this kind of problem. Ideas?

[welshpug 1,657]

check the Throttle Switch operation.

[Pete C 0]

check the Throttle Switch operation.

 

Checked it, clicks when throttle is closed.

[welshpug 1,657]

have you checked it with a multimeter? how well does it click closed?

 

ummm!

[Richie-Van-GTi 71 2 Cars]

air leak on intake.

[Grim.Badger 15]

air leak on intake.

 

Yep sounds like an air leak, a fairly big one at that. Check that the bolts on the side of the inlet manifold are still there as that is a fairly common place for a big leak.

[Rob_the_Sparky 9]

It could be the throttle not colsing properly when you let it off gently. Have a play under the bonnet.

 

If it is sluggish then check the ignition timing, they are quite commonly severly retarded in an attempt to get them to run on unleaded (95 RON). This also makes for a poor idle...

 

Rob

[lagonda 42]

Only logical reason for encountering different revs in reverse is that your engine mounts, especially the lower one, are loose or worn. Also your throttle cable may need adjusting, or may be clipped to the body area too tightly at some point. This would also explain kangarooing.