mk4 2.0 gti eating fuel

Hi

I have a 2.0 8v 1999 which since the cold snap and snow is now doing roughly 15mpg if that, nearly 45 miles on £15! There is a strong smell of unburnt fuel in and around the car which suggests too much is going through.

So far I have cleaned the MAF, throttle body and the creamy sludge build up out of the oil breather unit on the topside of the engine. I had a similar problem before which was due to the 02 sensor failing from a poor connection which I fixed under the car and I was back up to 30-35 mpg. This repair looks solid and still all taped up.

It does take more than a few miles for the temp guage to lift off the bottom, someone suggested a poor thermostat, but as I cant change this due to time, tools and the ice cold weather I need to be sure before I take it to a garage.

Any help or info much appreciated, I now these engines run bad in the cold but this is too expensive to drive round at the moment

Thanks

The thermostat opening too soon and over cooling the engine is a good possibility but this is normally shown by the gauge dropping as you are driving along at a steady speed. Unfortunately you have no alternative than to start with a fault code read, print, clear the codes, drive it again and re-read to see what comes back. If you try and fix it any other way you are guessing and will probably end up wasting money. Personally I do not find these engines run poorly in the cold weather, if anything they run better due to the lower inlet temperatures and denser air.

Hi, just to add that i had a similar problem to what you described. Changing the lamda sensor on the downpipe seems to have sorted it out.

cheers

i went through the wiring of the lamba after my diag said sensor 1 lambda was showing no activity, replaced all the wired joins from a previous sensor change by the previous owners, bit of a bodge job! i think some salt of the road got in the connections. next job is to check the plugs, change the thermo and a small service and ill be sweet. the re wire has got me back up to 30mpg ish :)