I recently purchased a 2003 a6 2.7t quattro. Sometimes I touch the gas and im thrown back into the seat... other times it feels about as strong as a n old air cooled beatle. When idling I hear a faint dull clicking sound. But it doesn't seem to be a lifter. Could the turbos kick out? Limp mode? Or maybe a coil pack acting up then working fine.

 

I would start by checking all the intake lines to look for a leak.

 

I do plan on doing that I just cannot figure out how that would make it intermitent.

 

Perhaps a faulty EGT sensor is causing the issue. If I am correct, a bad EGT sensor will not produce a CEL, but it will throw a code when you pull it up with vag com.

 

It's tough to find intermittent problems, but loss of boost could be caused by bad diverter valve or throttle body boot. Sorry - no can advise how to check them.

 

Sometimes the boot or any flexible connectors open up with temperature and movement. It can be intermittent.