Dodgy Idling and Lumpy sometimes?

[DavidKent]

As above...

1999 GTi with 122k.
Occasionally on idle it just starts running really lumpy, after 10 seconds sorts itself.

Also, on half throttle etc when driving it also goes lumpy / bogs - When i full throttle or lift off and go again it clears..

No EML, no Fault codes, nothing.
Full service about 2 weeks ago
Ran a Redex through

Still no ideas...

Any suggestions?

Cheers

[Aaron]

lambda?

[DavidKent]

No fault codes?

Only very intermittent too :/

[jimbo88]

Unfortunately this is quite a common problem for the vts/gti engines.
There are a few things to try:
• Ensure spark plugs were gapped correctly
• Clean throttle body and idle control valve (ICV)
• First cheaper thing you can try is to replace the coolant temperature sensor (around £10-15)
• If cleaning the ICV doesn’t work, use a friends’ ICV from a vts/gti that idles correctly/nicely and try it in your car. (If this does the job purchase a new one from Citroen or euro car parts – ones off of ebay on the whole seem to be no good)
• If still no luck, try in a friends coil pack from a vts/gti again that runs correctly to see if this remedy’s the problem. If so purchase a new one.

Doing all of the above will get you to the root of your problem –eventually!
Hope this helps,
Jimbo

[DavidKent]

Thanks for your help bud,

Done some of those, and it seems a touch better, still isn't right though - The idle control valve when unplugged makes no difference at all, which is a little odd?

I've a mate with a VTS off the road so i'm slowly using his parts to diagnose :)

Cheers

[ldavies]

You sure this hasent been cammed and running like it is due to needeing a map.

[DavidKent]

It only idles like it for about 10 seconds and sorts itself, it also seems pretty good on fuel so doubtful surely?

[Psycho18]

exact same problem mate. Only things left for me to change is MAP sensor, TPS sensor, Coilpack and ECU.

Have done any of those yet?

[DavidKent]

I haven't changed anything yet, was hoping to find someone with the same problem...

Unplugging my ICV does nothing when the car is running making me think that, there's no fault code, not even intermittent.

Cheers

[Psycho18]

No fault code on mine either. Get any further with this?

[saxovtrmk1]

Un plug lamba then take it for a run mine was exact same problem and doing this cured it.

[nathan9279]

I had the same problems and thanks to this thread I found the problem. Mine was the lambda

[Psycho18]

Un plug lamba then take it for a run mine was exact same problem and doing this cured it.

But without the lambda wouldn't it run like crap? Did you have a de-cat when you tried this?

[kennym1987]

But without the lambda wouldn't it run like crap? Did you have a de-cat when you tried this?

i have no lambda and mine runs perfect

[Psycho18]

i have no lambda and mine runs perfect

In that case it's worth a try.

[Cam]

i have no lambda and mine runs perfect

Mine dont it kept bogging down and juddering plugged it back it and it was fine, just dont ever want to idle.

[johnnyg_vts]

Injectors are notoriously problematic. Injector cleaner is shite. Buy a cheap second hand set of injectors, send them to be refurbed for about a tenner each. It'll be like a new car.

[nathan9279]

I unplugged my lambda sensor and that was the problem but haven't come round to replacing it, just a though would a vtr/vts lambda do the same job as the gti lambda? Because I have a space vtr lambda sat on my unused vtr engine
Thanks for the help guys

[kennym1987]

thats what i was thinking. maybe the vtr lambda would be the same? just to grab one from the scrappy and see as there are no 16vs in my area

[nathan9279]

I have a gti conversion in my vtr and I have the vtr engine in my shed. I was just wondering if the vtr lambda will be the same as the gti

[kennym1987]

try it and see. then let me know haha