Hello, I’m new here, I’ve been stuttering a lot but I’m still not quite conclusive what’s going on with my car… I changed my ignition coils about two months ago after a defective one. Otherwise, actually no problems have had so far… Now I have more often the Mkl lights, error p0135. Sometimes also p0171was it comes after I think… My question is now, can it be that the spark plugs have not survived the change of ignition coils and therefore I have problems with the lambda? I checked the circuit for obvious errors, lmm should also be fine, obd does not show so vaguely, temperature sensors should be loud obd also fine. What I noticed now, when the engine has run warm, which jumps to kat probe conspicuously, which does not do when the engine is cold. First 15 minutes by car the probe moves constant around the 0.7v…. When the engine is warm, it jumps once from 0.3 to 0.9…. & sw The before kat always moves between 0.1 and 0.9 … that should actually be normal… I honestly don’t know anything anymore at the moment. I don’t have any money to spend it unnecessarily in the ws …. would rather find and fix the mistake yourself. Vlt it really is just a wackler, I would be happy, but how can I find out? If now someone thinks I should measure through, please explain exactly how…?? I can really do a lot, but that’s one thing that doesn’t want to be in m a head Thanks already once in advance