Misfire - fr 3 plugs brown. rear 3 black sooty ?????

[MOM]

Hi. 

My t350 has just developed a misfire from idle. I checked the plugs & the front 3 are a nice light brown & the rear 3 black & sooty. (No 4 wet with fuel).
at first i thought it might be the coilpack but after posting on speedsix found it more likely to be a lambda sensor as the 2 operate the first 3 & back 3 cylinders. Only thing i dont understand is that i'm told the lambda's dont operate until engine is warm & my engine misfires hot or cold. Can anyone put me right on this ? Or any other ideas. I dont have any dash errors but must get a diagnostic cable.
regards
Mark

[craigcaf]

You really need the diagnostics cable and software. Could be an issue with one of the lambda sensors, or also one of the throttle pots. The diagnostics will help take the guesswork out.

You can then reset the adaptives and throttle pots, run it for a bit and see it that helps. I had a problem on mine and one of the throttle pot adaptives had gone high. Reset them with the diagnostics and fixed the problem - never happened again since.

[twinreal]

The lambda sensors have a heater coil to let them work before engine is hot.

[MOM]

Aha. Forgot the lambdas were heated.
Thanks C - have cable under construction & have downloaded the new sw from the speedsix forum here.
Thanks again twinreal.