IMHO, send that chip to Eric Marshall and give him your combo and get a new chip before you go too far.
If you insist on troubleshooting this setup...... got to get back to basics. Forgive me if I am breaking this down too simple.
Basically a chip is cut to provide a certain amount of fuel for a certain amount of airflow. It "reads" (among other things) the MAF meter which directly monitors all airflow coming into the engine. With a BLM that is too high..... this is an indicator that the ECM has basically added fuel to whatever was initially programmed into the chip. This is usually an indicator of "un-metered" air that has entered the system. This could be from (as simple as) a vacuum hose unhooked or split. It could be a gasket leak on the throttlebody or intake..... basically anywhere air can get into the engine without going through the MAF meter.
That is where I would start.
