mk4 2.0 gti eating fuel

[vw_craig]

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

[Crasher]

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.

[cammy9r]

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.

[vw_craig]

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