My Z is what seems to be misfiring and it started pretty randomly. The car was running perfect, I then had to do a camshaft replacement and after I replaced it the car still ran perfectly fine up until now which is about 2 weeks after I replaced the sensor. While driving the car at around 2kish rpms it would feel weird and I could hear a thumping sound coming from under the car and it sounded almost like an exhaust leak but then the car would go back to normal and would randomly do the same thing at around the same rpm’s sometimes. However, now the car has been doing it right after startup. At idle it starts making a thump like noise which sounds like “bump bump bump bump” repeatedly and I hear it the most pronounced around the y pipe area and before the cats. I am not sure what it could be I made sure it wasn’t an exhaust leak and the car is throwing P1283 and P0345 but I didn’t clear the P0345 code after replacing the camshaft sensor. Any help would be appreciated 👍

 

Welcome to the forum

 

Welcome- if your Z was "running perfect". why did you have to replace a cam? Have you tried putting the car up on jackstands and searching for the origin point of this thumping sound?