the car starts and idles from cold perfectly, but once warm it starts and dies/stalls straight away which is weird. it also idles a little unsteadier than it used to.

have run the car for about 150 miles since the MAF and let the initialisation finish before i started it first time after the MAF change.

it still feels like there is a tiny hesitation in power around 3k rpm and also the exact millisecond i let off the throttle power tails off quite suddenly which only seems since the new MAF.

im wondering if i need to be checking TBB or any other hoses etc to examine for tears or rips etc which from reading on here seem very common, but i dont know where to find the TBB on my 2000 a3 1.8 tsq

if anyones got any experiences of this, or advice etc then its greatly appreciated

thanks, dan

p.s - havent got an OBD for my vag com at the moment so cant plug it in for a code or anything

 

I would reset the ECU and perform a throttle body adaption if i were you. Disconnect the battery for 30 minutes or so. Turn the car on to the position just before starting. Let the car sit like this for 4 minutes or so. You should hear some clicking from the engine bay as the throttle body adapts. Make sure you have your radio theft code too.

 

tbb ???? I assume you mean throttle body or feed piping/throttle body butterfly plate? concentrate on the (IAC) idle control valve/stepper motor

 

1.8t's don't have idle air controls. They are electronically controlled through the throttle body.

 

that doesn't answer the question

 

it has a stepper motor and the throttle stop plate bends, difficult to explain

 

Citroen and other cars use this system, ill try to get some pictures of it

 

No it doesnt, it is controled excatly the way Jestnomen explained it

 

There is a stepper motor that actuates the butterfly valve in the throttle body. On the non drive by wire the stepper motor only corrects the movement to establish a controlled idle. On the drive by wire cars it controls all movement from idle to wide open throttle (WOT). Typically rough idles are caused by the throttle body needing to relearn the settings for a smooth idle. This is also called an adaptation or throttle body adaptation (TBA). Readings from MAF are calculated in determining the correct idle speed. Thus if a new MAF is installed it is conceivable that the engine could idle erratic as is the case here.

 

As I mentioned before, when I had this kind of problem (engine revs erratic, lack of power and random stalls) it turned out to be the engine speed sensor which was faulty. I strongly recommend reading the ECU fault codes to see where the problem might be...