[DRW1000]

Checking the hoses is a great first step. If you PCM is reading insufficieint flow it could be:

-insufficient flow due to clogged EGR ports
-the EGR not opening when commandeddue to a faulty EVM, clogged hose or faulty EGR.
-The DPFE itself
-The EGR valve

There are probably others. one trick is to let the engine idle and to apply a vacuum to the egr control line. If the EGR system is working it should stall the vehicle. You can also test the DPFE if you have access to a voltmeter. I have outlined the procedure inthe past (search under DPFE).

DPFEs are prone to fail so keep that in mind. Personally I would investigate a bit before replacing parts.

As for the hesitation and the o/d light. I think you have 2 unrelated problems. I would ensue that your transmission fluid is topped up as a start.