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Hey guys I am working on a 2005 Saturn Vue 3.5L. Customer had it at another garage for a idle surge and multiple misfires. They replaced 3 coil packs, injectors, spark plugs, valve cover and intake set.. typical parts changer. I found it to have rapid miss of cylinder 4. We tore it back down and found oil in 3 cylinders 2 Bosch plugs 4 autolites. We fixed the valve cover gasket leaks put the correct plugs in and new intake gaskets. Cleared codes and test drove was good for 3 days and now cylinder 3 has a rapid misfire. I was looking at the ckp waveform and it seems erratic but I have no way to verify the correct waveform. I have attached a picture of what I have. If anyone can see what it should look like or have any advice I appreciate it
I can't quite tell by the picture - What PID are we looking at exactly?
Can the miss be felt? Or is it only counting on the data?
I'd honestly say start over. Forget what parts have been thrown at it and treat it like a new vehicle. What are the trims on both banks during the misfire? If you raise the engine speed off idle, does the miss go away? What's the MAP voltage in Park at hot idle with no loads?
Treat it like a new vehicle. Do you Have a scope? This is a speed density honda engine you might get some direction with a scope faster than a scan tool due to communication speed