Hmm that's not good. It sounds like needs tune ups. Mine gets 34-36. When the last time maintenance done on to it?I recently purchased a 2006 Beetle w/1.9 tdi engine. Is it common to get 10 mpg less in winter than warmer weather? Struggeling to get 38 MPG now in 20 degree weather,,Mother is not happy!!
Anyone ever look at the coolant temperature to determine if the thermostat is soft and the engine is running too cold?
I do not work on the Diesels, but the engine temp would be the VERY first thing I would confirm.