Originally Posted by Willy337
Yesterday driving back the car suddenly starting running lumpy and was shaking me about, didn't feel smooth. It felt and sounding like it was misfiring. I got it connected upto VCDS Lite today and noticed that the lambda reading was showing -4.7% in the measuring blocks.
How do it fault find from here? Anybody got any suggestions?
02 sensors do NOT cause misfires...the front sensors only make minor fuel trim adjustments within a preset "map", AFTER the MAF has made the major main fuel/air mixture adjustment. The rear 02 sensors do nothing, except to report performance of front sensors and trip codes when called for.
Look elsewhere for your problem...if it was misfiring, the CEL would be flashing and VCDS would read misfire code(s).
One (of several) possibilities: A failing torque converter clutch, can mimic a misfire feel, especially at medium speed at light throttle.