Rev dipping when i break???

[hmeah]

when i break at lights or in traffic, the rev meter drops and bounces back up, it feels like the car might cut off & then comes back up to the usual point, does anyone know what this is & how i can get to sorted? i don't want to take it to a garage and people tell me 101 things.

i appreciate your help

[AndyHolmes]

Hi
I had this problem with my 1.8 T Sport and it turned out to be dirt in the throttle valve body not allowing the butterfly to seat/operate properly. I used carburettor cleaner sprayed onto the throttle valve and an old toothbrush to work it in and clean away any oil/dirt deposits. Could also be dirty/faulty maf sensor which is more delicate, but could be cleaned using carb cleaner alone, carefully so as not to damage the fine element inside. Hope this helps.

[hmeah]

thanks for the info, can you tell me where i can find the maf/throttle head to clean please?

[AndyHolmes]

The MAF sensor is located just after the air filter intake housing and is awkward to get at and remove. The throttle valve is easier to clean as it only involves loosening the jubilee clip that holds the rubber intake pipe onto the alloy throttle body housing and pulling it free. You can then get access to the throttle valve to spray carb cleaner up inside and use a toothbrush to clean, where necessary (a mirror is helpful here to look up inside the throttle body). Hope this resolves your issue, cheers.

[hmeah]

thanks, i have no idea where the jubilee clip is can you direct me in detail? thanks

Originally Posted by AndyHolmes

The MAF sensor is located just after the air filter intake housing and is awkward to get at and remove. The throttle valve is easier to clean as it only involves loosening the jubilee clip that holds the rubber intake pipe onto the alloy throttle body housing and pulling it free. You can then get access to the throttle valve to spray carb cleaner up inside and use a toothbrush to clean, where necessary (a mirror is helpful here to look up inside the throttle body). Hope this resolves your issue, cheers.

[AndyHolmes]

Not a great picture, but I've marked where the intake hose attaches to the throttle body, secured by a large jubilee clip. Should be apparent once you see it.

[rix1974]

I had the same problem with my 04 a couple of weeks ago. Turned out to be some type of sensor that controls the oxygen flow from the gas?? That is what the dealer told me. If you haven't already fixed the problem, let me know and I can give you the exact information that was on my bill from the dealer for repair.

[hmeah]

i cleaned what i thought was the throttle, seems like it slightly improved... i would appreciate the info and also the costing.

thank u

[rix1974]

The following was replaced when mine was acting up:
Mass Air Flow Meter
Part # VWN-06C133471AX
Part was $190
Labor was $200
Hope this helps if you start having problems again.