I was one of his problem suppliers. People would pay him for Landtank Products and I wouldn’t deliver.
In my defense my wife was going through a cancer incident and during that time I was shipping product and taking payment with out balancing the books. Once my wife was in the clear and I went...
that's exactly what would cause a lean error. You are drawing in air which the O2 sensor will see as un-burned oxygen and attempts to correct this by adding more fuel, which will have no effect, and eventually triggers a P0171, system too lean.
If you have the stock MAF and injectors still installed the timing pull is normal. Not sure about the AFRs but on a SC the pull happens and the AFRs stay rich. But a SC is belt driven and linear for the most part.