This is a dodge 3.6l van, known for cam, rocker and other cylinder head failures. The initial complaint was a misfire on cylinder 3. The customer was pretty car savvy, and was able to replace the plug, coil and injector with no change. As the misfire seemed to be progressing they opted to bring it in.

Basic testing confirmed the coil was firing, primary voltage waveform was confirming a misfire but had a good current ramp. The injector also showed good current ramps and voltage waveforms. The customer had located some damaged intake bolt.and replaced them with a different fastener so the intake was smoked to rule out a possible vacuum leak as the bolts were right at #3 - no leaks found. Vacuum gauge testing showed slight needle movement. Nothing too abnormal. Fuel pressure wasn't checked as the misfire was only effecting one cylinder. The fuel quality appeared to be ok. Statuc compression testing found roughly 150psi in all cylinders except #3 at 214psi. Running compression was a touch high in #3, and snap throttle actually a touch lower. While an in cylinder pressure transducer likely would have found this without valve cover removal, I don't yet have a pressure transducer.