Evzen

This usually occurs under full throttle after 4000-4200rpm, has happened in gears 2 to 5 and usually occurs when pushing the car above 150km/h+. At that point I cannot go any faster because this bogging: loss of engine power for a second or two, then it starts firing again, then a loss, then firing again...etc.

So far the dealership has been unable to locate any problems because they need an engine code to be set off for them to start working on my car (sounds like a catch 22 to me).
Here is what I have tried and my theories:

1) One time an engine code was triggered during the bogging down. Went to dealership and they told me some 'internal ECU codes' were set off. But that was the extent of it and they were unclear as to what it was. I then had the APR chip scanned by APR and nothing was found to wrong with it. To be safe I asked them to replace it with a stock one. Just got it back and problem still occurs.

2)OR...Turbo wear with 35k miles on high boost (car has 45k miles right now)?

3)Or maybe the BPV, which I changed last year. Did the little vacum hose loosen?

4) Or is the ECU faulty in some way or another?

I have another appointment tomorrow to get the car checked out for a mysterious missing seatbelt light (it is always off). I will also bring up the bogging thing and see I can take them on a 150km/h test drive.

Though at this point I am running out of options. The dealership is clueless as I am. If anyone has heard or experienced something similar on a turbocharged car in the past I would love to hear about it !

Thanks,
E.

EuroA4

Mine just got back from the dealer tonight. The other day, the car started hesitating completel, not just intermediately. I could barely even drive it, it was bucking, and gasping...it sounded really bad. Its a 2001.5 A4 1.8t with 25k miles....and they diagnosed the problem as a failed coil pack in cylinder #3. You might have one that is just about to fail, Just something to have them look at! Good luck.

Audi2ptzero

A coil pack will just go bad all at one time. Not at set rpms or just at WOT.

Audi2ptzero

If it was a bad ECU you would get a EPC light when you have the problem and that wont reset till you turn the key off.

Evzen

would that suggest spark plugs? or what about fuel injectors?

Audi2ptzero

If it is a spark plug you will get a misfire code and if it is a injector you will get a lean or rich code.

EPC light comes on if there is an issue with your ecu or you hit the tq limiter. But either way there will be a code for something when you look using the vag.

You might want to pull the plugs and check to make sure they are ok and regap them.

JAFO

my jetta had something like this. turn out to be water in the gas. this is the right time of year for this too. condensation in your or a station's tank could cause you to get large amount. try dry gas of some sort. this may happen on steep prolonged hills as depth of water increases over intake.

Dr.quattro

the software is sending to much boost. I bet it is the N75 valve. See about getting a new one from the dealer, or from someone on Audiworld or the vwvortex. I had a similar problem, so I replaced mine and it fixed the prob. Surging is the technical term....like you are on a roller coaster and the power comes, goes,comes,goes.....good luck...later.....

Audi2ptzero

Since I dont use a N75 valve to control my boost levels, I use a HKS EVC 4 boost controller and a chip.

Evzen

before I change the N75 valve.