Tech Advise

Hi I have an intermittent problem with the 'S' and was wondering if any if you have any ideas. I plugged in my diagnostic machine and drove about until the problem arose. It is a lack of power,{Miss fire/ fuel stutter} there isn’t any codes rearing there ugly heads however, the machine has showed that the Short Term Fuel Trim when running normally was at 0.0% but when the problem happened it went down to -32.9% the lower the number the more pronounced the stammer was. I have 2 questions first what is Short Term Fuel Trim and the 2nd what is needed to fix it {regulator on the fuel rail ect.} thanks
Nigel

The ECU is trying to lean out the fuel mixture because it thinks the car is running rich at that point (-% value means its trying to lean out, if it had been +% it would be trying to richen up the mixture).

It could be your decat, your oxygen sensor might be giving too high a reading.

I have had a brain wave .... I have been loking through the data and low and behold the E C Temp is 0, when having the problem... so i recon the water sensor is up the spout as it reads normally when running ok.......