mkongsiri

For some time now my 2005 A6 has been suffering from a rough idle after warm up. It almost sounded like it was missing at idle. Ive been running the car like this for some time now and decided to track it down. The only DTC Im getting on the VCDS is a malfunctioning CPS sensor which I've already ordered a replacement. Could this be a malfunctioning throttle? Again, not getting any fault codes.

mkongsiri

Well looks like again, google is my friend. This guy seems to have had the same problem, $30 used TB purchased. I could log into the VCDS and look at that controller real time but I think I'd rather finish my beer ;-)


His comments were:

"Canovic Villasin Jr1 year ago
After changing the spark plugs, Check for vacuum leaks, countless throttle adaptation - acceleration kick down procedure by using the vcsd, changed the MAF (mass air flow) sensor - the condition remain the same. I bought a used throttle body for $60 on eBay just to help me rule it out - and presto - I found the problem. It was a malfunctioned throttle body. I probably messed it up when I tried to clean it. I guess the sensor is very sensitive."

mkongsiri

Bad Throttlebody is confirmed. Installed used TB and new CPS and the car idles rock solid now.

mikerouze

Nice! Glad it was an easy fix.