HELP!! Problem with slight hesitation when coming off idle


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Dec 8, 2009
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I have an a3 1.8T AGU, recently had i chipped, car runs great and pulls very hard now, holding 16psi of boost now, however if i let the car idle right down and blip the throttle the car hesitates slightly, cant notice when driving accept when going down a hill, if you come back on the power i jerks. Also i think it may be running rich as i inspected the plugs and they were dry but black, if running the car on the drive for a bit i get nice black marks on my drive from exhaust. However the car is fine when driving, feels smooth and no hesitation. Cleaned maf, it had a new one last march. Any advice would be great.
Its was plugged in the other day when chipped and didn't return any prob, I have vag com my self and a £20 quid lead of flebay made by ecutools it a blue one, but i cant get it to communicate with the car, running vista. Anyone else had any luck with these leads or do i need to fork out for a genuine one?
i am suffering from this same problem mate when you press the accelerator in neutral does the rev needle have a hesitation on the way down
I dont know ill check later, ordered a new temp sensor, its the updated green version, for £10, worth a try, car has covered 100,000 and temp sensors are a week point and can cause overfueling. But would have thought a faultly one would give a error code.
Mine did it after the remap.

Clean the throttle body out and it should sort it.
Ok i will remove the throttle body, and clean right out, do i need to use vag com to allign the throttle body, ive heard on an agu that the throttle body will allign it self when ignition is turned on is this true. I think vista doesnt agree with the vag com lead and drivers i had.
Ok still no joy after cleaning the throttle body, just done 300 miles and the car behaves fine. Just the prob that it seems to overfuel when idling, and jerks bad when coming off the power going down a hill. lower gears are worst for it.
Mine seems to have the same problem,

i think its the plugs but havnt had chance to change them yet, i've been told to use copper plugs as they are a better conductor.

other than that it may be the fuel pump, unfortunatly its a process of elimination at the mo' as theres nothing coming up on Vagcom.

please let me know if anyone has the answer! as its been doing my nut in!

Fuel filter was done a month ago. Going to try the temp sensor when i arrives, as i understand if this is faulty then the car will choke at idle as i believes the engine has not yet warmed up, i will let you know if this helps.
One over thing does you temp display on the dash, normally come up to 90 and sit there. Or does it go down or struggle to reach 90 when driving??
right, thats interesting, so replace stat also, cheap parts at the moment so dont mind changing, where did you get your stat from? and is it a simple job? do you need to bleed coolant system after or just take cap off and run for a minute?
i paid a garage £15 to replace it because im lazy , but i know its not hard you have to refill water with anti freeze and bleed the system of air
£15 quid, think at that price i may go down the lazy route to, so it was the stat with the o ring? nothing else needed for the change?
you bought a cheap Vag-com lead from egay and a cheap temp sensor from egay too. think thats your problem. You get what you pay for.
Well to be honest i dont really want to pay the full price for a vag-com lead, people have used leads from "egay" with success, also the temp sensor is an oem part. Nothing else on the car has been replaced with anyhing from ebay so can rule that out. Think yourself lucky your engine isnt an agu, one day........ s3
Haha and you think the S3 will be problem free, just wait.
Ok i think that my problem may be coil pack related as it had a prob a month ago where the car would lose all power and sound like a scooby (running on 3) but after the service it seemed to go, but i think its causing this stutter when i blip the throttle off the idle. anyone else had this kind of issue when there coil packs started to die??
OK so its not coil packs, had a garage rule that out, also not the airflow meter, the idle fluctuates from time to time IE after touching the throttle drops to 600-500 then comes back to 900. only a small prob but it really bugs me
After hunting around i have found a small leak in the manifold, think its the gasket, a small puff of fumes/steam when starting from cold. and when it warms up you can smell it when you blip the throttle. What kind of adverse affects would a small leak like this cause?