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P1548 is probably a good place to start - clean/replace the air filter. The ECU is comparing barometric pressure to measured and modeled pressures along the intake tract. If the differences are significant, it'll infer that the air filter is clogged and providing restriction to the engine. It could also be worthwhile to check the charge pipes and BOV for leaking under boost - based on our investigation of how the code is triggered, I could see how a small post-turbo boost leak could mimic the fault conditions (small enough leak that the turbos can work harder to compensate for the underboost, avoiding an underboost code, but enough of a measured or modeled pressure differential that this code is thrown). The boost control system will attempt to correct for the restriction by running the turbos harder, which can create excess exhaust manifold pressure and contribute to misfiring.
Let me ask you this...
Since I removed the tune, I have had NO CELs even though I'm running SPD downpipes. I have done at least 10 WOT runs with no hesitation in any gears. I noticed at WOT the boost is just around 17 on the dash (yes I don't have a fancy boost gauge for accuracy and I'm back to stock PCM). Do you think that the added boost from the tune is asking too much from the engine and its over working everything that it takes to make more boost?
In laymans terms, if I never ran a marathon (stock engine), then all of a sudden I have to run a ******* marathon (tuned), I'm going to be over worked and dehydrated because me, the engine, has never had to work that hard. Again, I'm just curious that is all. Maybe I just need the PCM update from Ford or maybe there is a bigger issue...
Datalogs without the tune?
Datalogs without the tune?