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Discussion Starter · #1 ·
I am having an intermittent misfire. I am trying to find which cylinder is misfiring. I have MMcd. Is there anything in there that would log the misfire? If so, how to set up the logging for it? I also have the Mitsubishi/Dodge DRBII tool with the yellow cartridge. Is there anything in there that would log or capture a misfire?

This is for a first gen Stealth TT with the OBDI port.

Thanks!
 

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Unless there is a DTC, no, not really... you will need to test and troubleshoot by narrowing down possible culprits. If it is a random misfire, then it could be as simple as a vacuum leak(s). Cylinder-specific brings you to plug, coil, injector, etc.

-sent from my Galaxy Note 9
 

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Discussion Starter · #3 ·
Are there any good threads on vacuum leak testing for our cars? I have used smoke in the past for other vehicles. Also, if there is a vacuum leak, I should be able to monitor the fuel trim(s) and the O2 sensors, right?
 

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Yes, there have been a few notable threads with linked resources this past year - just run a search instead of creating a new discussion. And yes, those are good starting points in addition to a higher and/or oscillating idle rpm or significantly increased airflow/load reading at the same target boost all-else-equal.

-sent from my Galaxy Note 9
 

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I noticed that we can have an injection problem or intake leaks and the ECM wouldn't notice, it seems that the triggers for misfires are too permissive, you can check the fuel trims but I haven't been able to use those as I couldn't find the correct PID to log, usually the way to diagnose those hard to fix misfires is secondary ignition waveform analysis, but that is like a really advanced or experienced approach, the theory is easy and classroom examples are pretty straightforward but actually scoping the car for the first time with tons of weird signal noises, spikes and different patterns can throw you off.
 
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