I'm working with a 2009 Mustang 4.6. Ive tuned LS but not much Ford. That being said I can navigate and Get a few things done. Problem I'm having is customer brought to me thinking it needed a tune. Come to find out He had the car and ran it with current mods on a hand held SCT. Car ran fine. Did a clutch swap and randomly started having lean spike issue. Ive checked Fuel PSI and what I could see of the harness to make sure they didn't hurt it. Started tuning under the impression it just needed a tune as I was told. Car will run lean.... very lean. Like its got a quarter size vac leak. Found small vac leak and repaired. Found faulty injector clips and repaired. Car still lean. Ive adjusted the tune over and over trying to add fuel. Still lean. In closed loop after several min of run time and keeping it running the computer will shut off O2 sensors and car will idle right. Still lean via wide band, but it will act somewhat right. I adjusted the injector flow rate down a bit though to fake a force feed of fuel. (just a test) Acts better. Strange thing is I can not get the PCM to show me air flow in the histograms. ie No real movement on the MAF histo. No increase in vac on the MAP sensor. Do I have a corrupted PCM? Anyone ever have a random Fuel delivery problem? Here is a scan and a file. Please don't pick it apart This is just my current hail marry to try to get it to do something.