Turbo lag??? Acceleration problem.

[Condor]

I own an A4 Avant 2.5 TDI 180BHP / 132kw Multitronic 216,000km fully serviced.
Recently it has developed what I would describe as a lag between receiving an acceleration order and accelerating correctly, happens mainly in slow town driving i.e starting and stopping, but also when trying ¨kickdown¨. The symptom is a gradual acceleration with revs going up but the turbo doesn't kick in until it's overdue. As if the engine is holding it's breath. Any suggestions? I have an appointment for Wednesday afternoon in my Audi dealer, however he maintains that if nothing shows up on the Diagnostic computer, it may be quite tricky.????

[Condor]

Someone mentioned a possible defective¨Diverter valve¨ for the turbo...ring any bells with anyone???

[blancer]

Check the air intake to the motor. On my Jetta TDI that would get gummed up with junk/carbon residue and would need to be removed and cleaned.It really reduces the air flow from a 2" opening down to a .5" opening. After doing that the Turbo would sing and the car would fly. If it is plugged up it will kill the power. Especially at slow speeds. Just be careful not to let any carbon fall into the motor when you remove the intake. Let me know if that takes care of your problem. It needs to be cleaned every 40K miles or so unless you reprogram your computer with a vag-com like I did to eliminate the buildup.

[dperrone17]

My car was lagging a little also (2004 a4 1.8t) going back to see if i can get it cleaned out and also changing the oil while I am there. I have no idea if that is going to fix anything but it was time for it.

[bbishop]

I have a 2006 A4 Avant 2.0T. I have been told by the dealer that the lag is in the transmission. The transmission is not downshifting as fast as one steps on the accelerator. For example, in rolling to a stop and then accelerating, the transmission may not yet be in a low enough gear and takes time to catch up to your input. When passing on the highway and mashing the gas, the tranmsiion takes time to downshift. This sounds like a simple programming issue to me and the service tech agreed. I told them Audi will have a suit on their hands when someone is t-boned because they tried to get across traffic and the car does not respond quickly enough. I have had some close calls even when I thought I had plenty of room.

Anyone have any solutions?

[wkeast]

bbishop - Did you ever find a solution to the lag? My 2008 A4 is doing the same thing.

[bbishop]

no. I think the solution is a reprogramming of the computer that controls transmission shifts. I haven't found an aftermarket supplier. all the programs just focus on remapping for more hp.