Hello noob here so please direct me to the correct location if I'm doing it wrong. :/ I tried to search ASR.
I have a 2001 TT w/ 80k miles that started a 'surging' sporadically. I did some research and it appears that the car thinks it's losing traction or sliding because it seems to sporadically cut power. At first I thought it might be bad gas, but it idles fine.

I don't want to just start changing parts haphazardly - Does anyone know how to properly diagnose what I should be changing? The circle arrow around the triangle warning light came on a while after this started. The problem happens usually under part throttle, but will do it even when floored. Is this related to the ABS sensors? (the brake warning light did not light up)

Thanks for any assistance

 

I'd scan the ECU for any codes. If it's an ABS sensor, it will show up there. But here's a test you can do. Disconnect the MAF sensor in the airbox. Drive it (the Check Engine Light will come on) but if the surging and whatnot goes away, your MAF Sensor is the issue. The ECU can run the engine by compensating for the loss of the MAF Sensor. However, if the MAF sensor is sending faulty information about airflow, it can cause the ECU to make the engine do the things you mention. If it is the MAF sensor, you can remove it and clean it with some MAF Sensor spray (much like carb cleaner but us ONLY a cleaner designed for MAF sensors) and reinstall. If the issue goes away by cleaning the MAF, clear the codes on the ECU and you're done. Otherwise a new MAF is going to run about $200.

 

Thank you for the reply - I had serious doubts it would be the air flow sensor, but I disconnected it and the problem went away. I dug around and found the sender from another on the shelf and appears to be good now (we'll see how it does on the drive to work tomorrow. Thx again!! I owe you a beer